功能性高分子報告
題目: Comparison of spray pyrolyzed FTO, ATO and ITO
coatings for flat and bent glass substrates
比較FTO .ATO 與ITO塗層，利用噴霧裂解法在平的與彎曲的玻璃基板上
作者:
H. Bisht, H.-T. Eun1, A. Mehrtens, M.A. Aegerter
班級:化材四甲
姓名:江倢瑩
學號:49740019
Abstract
Transparent conductive FTO, ATO and ITO ®lms were synthesized by spray pyrolysis technique on
flat 12 £ 12 cm borosilicate glass substrates at 500±5508C and investigated with respect to their
electrical and optical properties. The resistivity of sprayed ITO ®lms decreases with the
thickness down to 3:0 £ 1024 V cm (300 nm). The optical transmission in the visible range is 80%
and the near IR reection up to 96% for thicknesses larger than 300 nm. A reducing treatment at
4008C in forming gas still decreases the resistivity by a factor of two.
Bending of the coated glasses in air at 6508C for 1.5 h increases the resistivity of the coatings
on the tensile side of the substrate by a factor of 3±4 and by a factor 2 on the compressed side.
A subsequent reducing treatment in forming gas at 4008C leads to a drastic decrease of resistivity
in both cases by a factor of 5±7 with resulting value r . 2±3 £ 1024 V cm. ATO layers have lower
visible transmission (70±75%) due to stronger absorption and a higher resistivity (r . 1 £ 1023
V cm). Spray pyrolyzed FTO coatings have a resistivity r . 5 £ 1023 V cm for ®lm thicknesses .350
nm. q1999 Elsevier Science S.A. All rights reserved.
摘要
透明導電 FTO，ATO和ITO在LMS合成上被噴上12英鎊12厘米的裂解技術，高的硼
矽玻璃基板在500±5508C上和其電學方面和光學性質來進行調查。噴 ITO LMS的
電阻率隨厚度下降到3:0英鎊1024 V CM（300海裡）。在可見光範圍內的光傳輸是
80％和近紅外線重新形成的厚度大於300奈米到96％。在4008C中形成的氣體，是
減少治療和降低電阻率的兩個因素。
1. Introduction
The high transmittance in the visible spectral region in combination with a high
conductivity, and a high re¯ectance in the IR region of non-stoichiometric and doped
®lms of oxides of tin, indium, cadmium and zinc is still of wide interest due to their
broad applications in electronic and
optical devices, like transparent electrodes for display devices, gas sensors, heating
elements in aircraft and car windows for defogging and deicing, etc. [1]. These coatings
have been deposited by various methods such as chemical vapor deposition (CVD), reactive
RF sputtering, evaporation, atomic layer epitaxy, spray pyrolysis and sol-gel processes
[2]. This paper compares the properties of pyrolytically
sprayed ATO, FTO and ITO ®lms deposited under nearly identical conditions. The effect
of dopant concentration and coating thickness as well as heat treatment under a reducing
atmosphere on the electrical and optical properties of the lms are described. The
in¯uence of a bending process on
the electrical properties of ITO lms is also reported.
1.簡介
在可見光譜區的高透光率中結合高導電，在紅外線區域的非化學計量來摻雜 LMS
錫氧化物，銦，鎘，鋅，依然是由於廣泛的應用電子和光學設備的利益，如顯示
器的透明電極設備，氣體傳感器，加熱元件，在飛機和汽車除霧和除冰的窗戶。
這些塗料已通過各種方法，如化學沉積、氣相沉積（CVD）反應磁控濺射，蒸發，
原子層外延，噴霧熱解法，溶膠 - 凝膠流程。本文來比較FTO .ATO 與ITO塗
層，利用噴霧裂解法在平的與彎曲的玻璃基板上。來摻雜濃度和效果塗層厚
度以及減少熱處理下的電學和光學性質
2. Experimental
2.1. Spray process and sample characterization
The solutions were sprayed on hot borosilicate substrates of 12 £ 12 cm size, heated
from the backside by a ceramic heater. The temperature of the glass surface was measured
with a pyrometer (Heimann KT 19.43, 7.5±8.2 mm). The spraying process was done with a
conventional hand spray gun (SATA Mini Jet) equipment with a 0.5 mm nozzle using
compressed air (1±2 bar) and a solution ¯ow rate of 13± 17ml/min. To avoid a too strong
cooling of the substrate by the compressed air an interval spraying procedure of 3 s
of spraying period followed by an interruption for about 30 s
was used. The ®lm thickness, t, was measured with a Tencor P10 pro®lometer and the sheet
resistance, RA, as well as carrier density, n, and Hall mobility, m, were measured with
the Van der Pauw method (MMR Technologies, Inc.). The electrical resistivity, r , was
determined by the relation r . RAt. Transmission and near normal (78) re¯ection of the
sprayed layers were measured with a Cary 5E spectrometer from 300 nm to 3 mm and the
re¯ection in the IR from 3 to 20 mm IR range with a Bruker IFS 66v FTIR spectrometer.
2.實驗
2.1噴塗工藝和樣品表徵
被噴上12英鎊12厘米大小，由陶瓷背面的加熱器來加熱，來解決熱硼矽基板的方
式。玻璃的表面溫度測量用測溫儀（海曼KT19.43，7.5±8.2毫米）。噴塗過程中
與傳統的手工噴槍（SATA微型噴氣）為設備用0.5毫米的噴嘴採用壓縮空氣（1±
2bar）
。為了避免過於強烈，基板冷卻壓縮空氣噴塗過程約30秒中分為3次噴塗。
T，是被衡量一個 Tencor P10 PRO lometer和薄膜電阻，RA，以及載流子密度，
N和霍爾遷移率，M，測量與范德堡方法（MMR疫苗技術公司。）電阻，R，是由關
係 R。RAt。從300奈米到3毫米，在紅外線重新生成3~20毫米，採用 Bruker IFS66V
紅外線光譜儀的紅外線範圍與Cary 5E光譜儀分別測量傳輸和接近正常的質。
2.2. Preparation of spraying solutions
For FTO layers a commercially available ethanolic solution (OTN 3-5, Goldschmidt AG)
of monobutyltintrichloride (MBTC) doped with 3 wt.% HF was used. The substrate
temperature was 5008C. For ATO layers a 0.24 M ethanolic solution of SnCl4´5H2O (solid
content 83 g/l ethanol) doped
with 1±5 mol.% SbCl3 (molar ratio Sb:Sn) was used. The substrate temperature was 5508C.
For ITO layers a 0.36 M solution of InCl3 in an ethanol/water mixture (weight ratio 1:1)
was sprayed at a substrate temperature of about 5208C. The solution was stabilized by
adding 7.5 g HCl to 100 ml of
the mixture.
2.2.製備的噴塗解決方案
對於FTO導電層摻 monobutyltintrichloride（MBTC）市售的乙醇溶液含3 WT％
的HF。基本溫度為5008C。對於 ATO層的SnCl4'5H2O一個0.24M的乙醇溶液（固體
含量83克/升乙醇）摻雜1±5 mol％的SbCl3（莫耳比銻：錫）來被使用。基本溫
度為5508C。 ITO層的InCl3為0.36M，乙醇/水混合物（重量比1:1）溶液噴灑在
基底溫度大約5208C。解決的辦法是加入7.5克鹽酸配置100毫升的混合物來穩定。
2.3. Bending and reducing treatment
Bending experiments were carried out for ITO layers in a furnace under air at 6508C.
Flat coated substrates were laid on a curved steel mold with a radius of curvature of
50 cm and bent under their own weight during 1.5 h. The experiments were done in two
ways: the substrate was laid onto a
steel mould such that the coating was either elongated (tensile bending) or compressed
(compressive bending). A reducing treatment was then carried out for flat and bent ITO
samples in forming gas (92% N2, 8% H2, flow rate 70(l/h) at 4008C during 15 min.
2.3。彎曲和減少處理
彎曲實驗在6508度在TO層被攜帶出空氣。平塗基板下被縮減鋼模為曲率半徑 50
厘米和彎曲，並實驗根據自己的體重在1.5小時在兩個方面上：基板上閒置
模具鋼等塗層拉長（拉伸彎曲）或壓縮（壓縮彎曲）。來減少處理氣體的形成。
3. Results and discussion
3.1. Electrical properties of ATO coatings In Fig. 1 the resistivity of ATO layers with
different antimony concentrations is plotted versus the ®lm thickness. The lowest values
are obtained for dopant concentrations in the range from 1 to 3 mol.%Sb. For lower and
higher doping the resistivity is higher for all ®lm thicknesses. Sheet resistance as
low as 20 VA can be obtained for a ®lm thickness
of 400 nm (Fig. 4). In Fig. 2 the resistivity, r , the carrier concentration, n, and
the mobility,m, are plotted for about 300 nm thick ATO ®lms as a function of the antimony
concentration. The
undoped SnO2 coating has very low intrinsic carrier density and mobility. For the doped
ATO samples m decreases always by almost the same factor by which n simultaneously
increases. This behavior is the reason for the independence of r in the Sb concentration
range of 1±3 mol.%.
3.結果與討論
3.1.電阻率是不同的銻含量的ATO層繪製的與LM的厚度。最低值得到的摻雜濃度
範圍是從 1到3 莫耳％SB。對於較低和較高的摻雜電阻率來比較高，厚度為所有
LM表示20 VA低電阻，便可獲得一個LM厚度為400奈米。電阻率，載流子濃度，N，
和流動性，M，R，繪製約 300 nm厚的ATO來分辨銻濃度函數的LMS。未摻雜SnO2
奈米塗層具有非常低的本徵載流子密度和流動性。對於摻雜ATO樣品跌幅幾乎相
同的因素，其中n同時增加。這種行為是銻在濃度範圍內的原因，為獨立的R±3 MOL
％。
3.2. Electrical properties of ITO coatings
Fig. 1 shows also the resistivity of ITO layers with Sn dopant concentrations of 2.4
and 4.8 mol.% (atomic ratio Sn/In). For thicknesses t . 100 nm resistivities of 3±4 £ 1024
V cm are obtained for nearly all investigated samples. A reducing treatment in forming
gas at 4008C slightly decreases the resistivity down to r . 1:8±2:8 £ 1024 V cm for
thicknesses .80 nm, the best results being reached
with the highest dopant concentration. A reducing treatmentunder forming gas for 15 min
at 5008C increases the resistivity above the initial as-sprayed level in contrast to
the reducing treatment at 4008C. In addition the samples show a slightly black metallic
cosmetic appearance due to a partly
reduction of the oxide layers into metallic indium. In Fig. 3 the values of r , n and
m are shown as a function of the dopant concentrations. The thickness of all layers was
about 240 nm. With increasing Sn concentration in the solution from 0 to 3 mol.%, n
increases strongly reaching a maximum for about 5 mol.% Sn. For higher dopant content
no more Sn-atoms can be embedded in the In2O3-lattice, as the maximum solubility of
Sn-atoms in the In2O3-lattice is limited to about 5 mol.% [3]. The decrease of the carrier
density for higher Sn concentration may be due to interstitial Sn-atoms in the lattice
which act as charged trapping centers for the electrons. A phase separation of small
SnO2-particles
in the crystalline ITO-material does not occur since no Bragg re¯exes belonging to a
crystalline SnO2 phase was detected in XRD measurements. The mobility m decreases from
high values of about 35
cm2/Vs for the undoped state down to below 20 cm2/Vs for higher dopant content. This
is due to the increasing number of Sn-atoms in the crystal lattice which act as ionized
scattering centers when localized on interstitial lattice sites or to a strongly
distorted crystal structure due to the radius mismatch. As a result the resistivity shows
a minimum of r . 2:5 £ 1024 V cm around 3 mol.% Sn concentration. For lower and higher
concentrations the resistivity exhibits higher values due either to low n values and/or
to a decrease of m. Only dopant concentrations between 2.4 and 4.8 mol.% were used for
further investigations.
3.2.電氣性能的ITO塗層
ITO的電阻層與錫摻雜濃度為 2.4和4.8莫耳％（原子比錫 / 鉈）
。對於厚度 100
奈米電阻率的3 ± 4英鎊 1024 V CM獲得了幾乎所有的解釋。 4008C中形成的減
少處理氣體有下降的電阻為 R。 1:8 ± 2:8英鎊 1024 V為厚度的和0.80奈米厘
米，最好的結果達成摻雜濃度最高。在5008C的15分鐘減少實驗所產生氣體噴霧
4008C減少處理的初始水平以上的電阻率增加。此外，樣品展示一個略帶黑色金
屬美觀，由於一個部分還原成金屬銦的氧化層。R，N和M的值顯示為摻雜濃度的
函數。所有層的厚度約為 240奈米。增加錫的濃度從 0到3 莫耳％的解決方案。
n的增加強烈達到約 5 莫耳％最大的錫。錫濃度在較高的載流子密度下降可能是
由於間質的晶格作為收取電子誘捕中心錫原子。一個小型SnO2奈米顆粒的相分離
而在結晶 ITO材料不會發生，因為沒有布拉格重新重製屬於一種結晶二氧化錫相
的EXE，在X射線衍射測量檢測。流動下降到約 35的高值cm2/Vs摻雜的狀態下以
較高的摻雜含量低於 20 cm2/Vs。這是由於越來越多的錫原子晶格中離子散射中
心本地化間質性格點或強烈扭曲的晶體結構，由於半徑不匹配時，。因此，電阻
率顯示了R的最低。 2:5英鎊 1024 V CM左右的3 莫耳％的錫濃度。對於濃度較
低和較高的電阻率表現出較高的值，由於低n值和/或減少分枝摻雜濃度只有2.4
和4.8 莫耳％之間。而可用於進一步調查。
3.3. Electrical properties of FTO coatings
The resistivity of FTO coatings is also plotted versus the ®lm thickness in Fig. 1. It
slightly decreases with the increase of the thickness and values as low as r .3:5 £ 1024
V cm are reached for thicknesses larger than 500 nm. The mobility increases linearly
with the ®lm thickness from 10 to about 25 cm2/Vs until a thickness of about 600 nm is
reached. The reason may be a linear increase in the crystal size in the growing ®lm with
increasing ®lm thickness resulting in a linear increase in mobility due to better
contacts between neighbored crystallites. In the thickness range up to 600 nm the carrier
density is nearly independent of thickness with showing values ranging between 4.5 and
6 £ 1020 cm23.
For thicknesses higher than 800 nm the values of m and n scatter in opposite direction
resulting in an almost constant value in resistivity of about 3:5 £ 1024 V cm as can
be seen in Fig. 1. The scattering of the values may be a consequence of the long term
heating at 5008C of the ®lms during the spraying process which lasts for about half an
hour for a layer thicker than 1 mm due to the interval spraying method
3.3.FTO導電塗料的電性能
FTO導電塗料的電阻率也與LM厚度有關係。它略有下降3:5英鎊1024 V CM厚度大
於500奈米來達成與低增長的厚度和價值觀。LM厚度從10至約25 cm2/Vs線性的流
動性增加，直到達到厚度約 600奈米。其原因可能是在晶體尺寸在日益增加LM
由於離子晶粒之間更好的聯繫，在流動的線性增加厚度LM線性增加。在600奈米
的厚度範圍的載流子密度幾乎是獨立的厚度的顯示值介於4.5和6英鎊1020 CM23
之間。厚度高於800 nm的m和n電阻率幾乎不變的價值約3005英鎊1024 VCM，因而
可以看到在對面方向的散射值。在噴塗過程中可以持續約一個半小時為小於1毫
米厚的一層，由於使用間隔噴霧法，散射的值可能是長期加熱的結果。
3.4. Comparison of the electrical properties
A comparison of the plots shows that the resistivity of ATO ®lms with an optimum Sn
concentration of 3 mol.% is the highest for all ®lm thicknesses. The ITO layers and
especially the reduced ITO coatings show the lowest values whereas the values of the
FTO layers lay in between. For technical application it is interesting to plot the sheet
resistance versus ®lm thickness. Fig. 4 shows a log-log plot of the results obtained
for the different materials. As the resistivities do not vary drastically with the
thickness all the results lie on straight lines as RA . r=t. Whereas the ATO coatings
with optimum Sn concentration of 3 mol.% result in a sheet resistance as low as 20 VA
for a ®lm thickness of 400 nm, the FTO layers show lower values of about 15 VA for the
same ®lm thickness. The best results are obtained for ITO coatings that are treated in
a forming gas atmosphere. This reducing treatment results in a decrease in the sheet
resistance, RA, of nearly a factor 2. For example, a 250 nm thin ®lm with R . 18 VA in
the as-sprayed state decreases to about RA . 8 VA after reduction. For thicknesses .400
nm sheet resistances as low as 5 VA can be reached by this reducing treatment. In Fig.
5 m is plotted versus n for all investigated ITO, FTO and ATO samples. The values obtained
from various spraying solutions are always situated in a limited region independently
of the individual ®lm thickness. The ATO layers follow a speci®c trend with increasing
Sb concentration from 1 to 5 mol.%: n increases steadily whereas m decreases. All data
points in this plot are below the straight line given by the Johnson and Lark±Horovitz
law which describes how much the mobility decreases in fully degenerated semiconductors
when the carrier density increases [4,5]: m < .4e=h..p=3.1=3N22=3 .1. The data for the
FTO and ITO layers are above this line. The reducing treatment of the ITO layers in forming
gas shifts
the data simultaneously to higher n and smaller m values on a line parallel to the
calculated line. Hence these reduced samples also follow the trend of the law of Johnson
and Lark±Horovitz but the values for the ITO samples are shifted to higher values.
3.4.電氣性能的比較
電阻 ATO和LMS最佳的錫濃度為3 mol％，是為所有LM厚度最高。ITO層是特別減
少 ITO塗層顯示的最低值，而對 FTO層之間的價值觀打下。對於技術的應用，它
是LM厚度薄膜電阻。電阻率不隨厚度大幅所有的結果在於作為 RA直線。 R = T。
鑑於在ATO塗料具有最佳的錫濃度的3 mol％結果在20 VALM厚度為 400奈米的低
片電阻，FTO導電層顯示相同的LM厚度降低約 15 VA值。獲得最好的結果是形成
氣體氛圍處理的ITO塗層。這在一個工作表中的阻力減少，RA近的一個因素，減
少處理效果。例如，一個 250 nm的薄LM與R。18日在噴霧狀態 VA降低因天雨。 8
VA還原後。對於厚度0.400 nm的表電阻低5 VA可以達到這個降低治療。所調查的
ITO，FTO和ATO樣品繪製與 n為 5米。從各種噴塗解決方案得到的值總是位於一
個獨立的個體LM厚度有限的區域。ATO層遵循特定的趨勢，隨著銻的濃度從 1到5
莫耳％n的增加而隨穩定使M減小。
3.5. Effect of bending on the electrical properties
Bending treatments were done with the sprayed ITO coatings of 2.4 and 4.8 mol.% Sn
concentration. To examine the in¯uence of the bending process each as-sprayed substrate
was cut into four individual smaller pieces which were submitted to the following
procedures:
1. Piece one was measured, forming gas (FG) treated, and measured again.
2. Piece two was subjected to tensile bending, measured, FG treated, and measured again.
3. Piece three was subjected to compressive bending, measured, FG treated, and measured
again.
4. Piece four was only heat treated without bending under the same heating conditions
(6508C for 1.5 h), measured, then FG treated, and measured again. Fig. 6 shows the
resulting sheet resistances, RA, as a function of the ®lm thickness of samples sprayed
with the solution containing 2.4 mol.% Sn. A similar behavior has been obtained with
the 4.8 mol.% Sn doping. RA increases by a factor of 1.8 for layers submitted to
compressive bending and by a factor 3 for layers submitted to tensile bending. The
samples heated under the same conditions without bending show values between these for
most of the investigated thicknesses (factor 2.2). The FG treatment results in a strong
decrease of RA for all four types of samples. The as-deposited samples show a decrease
to 0.55 of the initial assprayed state. The strongest decrease is observed for the samples
subjected to tensile bending (factor 7.2), those ones subjected to compressive bending
show a decrease by a factor of 4.6 while the only heated samples show a decrease by a
factor of 3.5. It is interesting to note that both types of bent samples exhibit nearly
identical results after the reducing treatment with values of sheet resistances lower
than those of flat samples directly reduced from the as-sprayed state. The bending and
subsequent reducing treatment results in values of about 5±7 VA for ®lm thicknesses
between 280 and 430 nm. Fig. 7 shows a plot of m versus n of the samples shown in Fig.
6. Samples that have been subjected to the same treatment
are surrounded by a circle or an ellipse. As-sprayed samples subjected to tensile bending
as well as samples only heated at 6508C exhibit a strong decrease of n and m, whereas
the compressed coatings show only a decrease in n. It is believed that in compressive
bending a closer contact
and a higher densi®cation occurs at the contact areas between the crystalline particles
in the layer which roughly compensates the decrease in m detected in the only heated
and tensile bent layers. The observed decrease in n in all cases is probably due to an
oxidation of the non-stoichiometric oxide layers subjected to the high temperature of
6508C. This results in a decrease of the number of vacancies in the oxygen sublattice
and probably also to an increasing number of excess oxygen atoms situated at interstitial
sites in the crystal lattice. These electrically charged excess oxygen atoms
lead to ionic scattering centers which decrease the mobility in the ITO ®lms. The
subsequent FG treatment reverses this effect and results in a higher oxygen de®ciency
in the oxygen sublattice than it was present in the initial assprayed state. As a
consequence n increases from the initial value of 3:5 £ 1020 cm23 to about 6 £ 1020 cm23
for the bent and only heated samples. At the same time the mobility
increases signi®cantly for both kinds of bent samples probably because of a decrease
of the number of the ionic oxygen scattering centers in the crystal lattice due to the
loss of oxygen ions at the interstitial sites.
3.5. Effect of bending on the electrical properties
Bending treatments were done with the sprayed ITO coatings of 2.4 and 4.8 mol.% Sn
concentration. To examine the in¯uence of the bending process each as-sprayed substrate
was cut into four individual smaller pieces which were submitted to the following
procedures:
1. Piece one was measured, forming gas (FG) treated, and measured again.
2. Piece two was subjected to tensile bending, measured, FG treated, and measured again.
3. Piece three was subjected to compressive bending, measured, FG treated, and measured
again.
4. Piece four was only heat treated without bending under the same heating conditions
(6508C for 1.5 h), measured, then FG treated, and measured again. Fig. 6 shows the
resulting sheet resistances, RA, as a function of the ®lm thickness of samples sprayed
with the solution containing 2.4 mol.% Sn. A similar behavior has been obtained with
the 4.8 mol.% Sn doping. RA increases by a factor of 1.8 for layers submitted to
compressive bending and by a factor 3 for layers submitted to tensile bending. The
samples heated under the same conditions without bending show values between these for
most of the investigated thicknesses (factor 2.2). The FG treatment results in a strong
decrease of RA for all four types of samples. The as-deposited samples show a decrease
to 0.55 of the initial assprayed state. The strongest decrease is observed for the samples
subjected to tensile bending (factor 7.2), those ones subjected to compressive bending
show a decrease by a factor of 4.6 while the only heated samples show a decrease by a
factor of 3.5. It is interesting to note that both types of bent samples exhibit nearly
identical results after the reducing treatment with values of sheet resistances lower
than those of flat samples directly reduced from the as-sprayed state. The bending and
subsequent reducing treatment results in values of about 5±7 VA for ®lm thicknesses
between 280 and 430 nm. Fig. 7 shows a plot of m versus n of the samples shown in Fig.
6. Samples that have been subjected to the same treatment
are surrounded by a circle or an ellipse. As-sprayed samples subjected to tensile bending
as well as samples only heated at 6508C exhibit a strong decrease of n and m, whereas
the compressed coatings show only a decrease in n. It is believed that in compressive
bending a closer contact
and a higher densi®cation occurs at the contact areas between the crystalline particles
in the layer which roughly compensates the decrease in m detected in the only heated
and tensile bent layers. The observed decrease in n in all cases is probably due to an
oxidation of the non-stoichiometric oxide layers subjected to the high temperature of
6508C. This results in a decrease of the number of vacancies in the oxygen sublattice
and probably also to an increasing number of excess oxygen atoms situated at interstitial
sites in the crystal lattice. These electrically charged excess oxygen atoms
lead to ionic scattering centers which decrease the mobility in the ITO ®lms. The
subsequent FG treatment reverses this effect and results in a higher oxygen de®ciency
in the oxygen sublattice than it was present in the initial assprayed state. As a
consequence n increases from the initial value of 3:5 £ 1020 cm23 to about 6 £ 1020 cm23
for the bent and only heated samples. At the same time the mobility
increases signi®cantly for both kinds of bent samples probably because of a decrease
of the number of the ionic oxygen scattering centers in the crystal lattice due to the
loss of oxygen ions at the interstitial sites.
3.5. Effect of bending on the electrical properties
Bending treatments were done with the sprayed ITO coatings of 2.4 and 4.8 mol.% Sn
concentration. To examine the in¯uence of the bending process each as-sprayed substrate
was cut into four individual smaller pieces which were submitted to the following
procedures:
1. Piece one was measured, forming gas (FG) treated, and measured again.
2. Piece two was subjected to tensile bending, measured, FG treated, and measured again.
3. Piece three was subjected to compressive bending, measured, FG treated, and measured
again.
4. Piece four was only heat treated without bending under the same heating conditions
(6508C for 1.5 h), measured, then FG treated, and measured again. Fig. 6 shows the
resulting sheet resistances, RA, as a function of the ®lm thickness of samples sprayed
with the solution containing 2.4 mol.% Sn. A similar behavior has been obtained with
the 4.8 mol.% Sn doping. RA increases by a factor of 1.8 for layers submitted to
compressive bending and by a factor 3 for layers submitted to tensile bending. The
samples heated under the same conditions without bending show values between these for
most of the investigated thicknesses (factor 2.2). The FG treatment results in a strong
decrease of RA for all four types of samples. The as-deposited samples show a decrease
to 0.55 of the initial assprayed state. The strongest decrease is observed for the samples
subjected to tensile bending (factor 7.2), those ones subjected to compressive bending
show a decrease by a factor of 4.6 while the only heated samples show a decrease by a
factor of 3.5. It is interesting to note that both types of bent samples exhibit nearly
identical results after the reducing treatment with values of sheet resistances lower
than those of flat samples directly reduced from the as-sprayed state. The bending and
subsequent reducing treatment results in values of about 5±7 VA for ®lm thicknesses
between 280 and 430 nm. Fig. 7 shows a plot of m versus n of the samples shown in Fig.
6. Samples that have been subjected to the same treatment
are surrounded by a circle or an ellipse. As-sprayed samples subjected to tensile bending
as well as samples only heated at 6508C exhibit a strong decrease of n and m, whereas
the compressed coatings show only a decrease in n. It is believed that in compressive
bending a closer contact
and a higher densi®cation occurs at the contact areas between the crystalline particles
in the layer which roughly compensates the decrease in m detected in the only heated
and tensile bent layers. The observed decrease in n in all cases is probably due to an
oxidation of the non-stoichiometric oxide layers subjected to the high temperature of
6508C. This results in a decrease of the number of vacancies in the oxygen sublattice
and probably also to an increasing number of excess oxygen atoms situated at interstitial
sites in the crystal lattice. These electrically charged excess oxygen atoms
lead to ionic scattering centers which decrease the mobility in the ITO ®lms. The
subsequent FG treatment reverses this effect and results in a higher oxygen de®ciency
in the oxygen sublattice than it was present in the initial assprayed state. As a
consequence n increases from the initial value of 3:5 £ 1020 cm23 to about 6 £ 1020 cm23
for the bent and only heated samples. At the same time the mobility
increases signi®cantly for both kinds of bent samples probably because of a decrease
of the number of the ionic oxygen scattering centers in the crystal lattice due to the
loss of oxygen ions at the interstitial sites.
3.5. Effect of bending on the electrical properties
Bending treatments were done with the sprayed ITO coatings of 2.4 and 4.8 mol.% Sn
concentration. To examine the in¯uence of the bending process each as-sprayed substrate
was cut into four individual smaller pieces which were submitted to the following
procedures:
1. Piece one was measured, forming gas (FG) treated, and measured again.
2. Piece two was subjected to tensile bending, measured, FG treated, and measured again.
3. Piece three was subjected to compressive bending, measured, FG treated, and measured
again.
4. Piece four was only heat treated without bending under the same heating conditions
(6508C for 1.5 h), measured, then FG treated, and measured again. Fig. 6 shows the
resulting sheet resistances, RA, as a function of the ®lm thickness of samples sprayed
with the solution containing 2.4 mol.% Sn. A similar behavior has been obtained with
the 4.8 mol.% Sn doping. RA increases by a factor of 1.8 for layers submitted to
compressive bending and by a factor 3 for layers submitted to tensile bending. The
samples heated under the same conditions without bending show values between these for
most of the investigated thicknesses (factor 2.2). The FG treatment results in a strong
decrease of RA for all four types of samples. The as-deposited samples show a decrease
to 0.55 of the initial assprayed state. The strongest decrease is observed for the samples
subjected to tensile bending (factor 7.2), those ones subjected to compressive bending
show a decrease by a factor of 4.6 while the only heated samples show a decrease by a
factor of 3.5. It is interesting to note that both types of bent samples exhibit nearly
identical results after the reducing treatment with values of sheet resistances lower
than those of flat samples directly reduced from the as-sprayed state. The bending and
subsequent reducing treatment results in values of about 5±7 VA for ®lm thicknesses
between 280 and 430 nm. Fig. 7 shows a plot of m versus n of the samples shown in Fig.
6. Samples that have been subjected to the same treatment
are surrounded by a circle or an ellipse. As-sprayed samples subjected to tensile bending
as well as samples only heated at 6508C exhibit a strong decrease of n and m, whereas
the compressed coatings show only a decrease in n. It is believed that in compressive
bending a closer contact
and a higher densi®cation occurs at the contact areas between the crystalline particles
in the layer which roughly compensates the decrease in m detected in the only heated
and tensile bent layers. The observed decrease in n in all cases is probably due to an
oxidation of the non-stoichiometric oxide layers subjected to the high temperature of
6508C. This results in a decrease of the number of vacancies in the oxygen sublattice
and probably also to an increasing number of excess oxygen atoms situated at interstitial
sites in the crystal lattice. These electrically charged excess oxygen atoms
lead to ionic scattering centers which decrease the mobility in the ITO ®lms. The
subsequent FG treatment reverses this effect and results in a higher oxygen de®ciency
in the oxygen sublattice than it was present in the initial assprayed state. As a
consequence n increases from the initial value of 3:5 £ 1020 cm23 to about 6 £ 1020 cm23
for the bent and only heated samples. At the same time the mobility
increases signi®cantly for both kinds of bent samples probably because of a decrease
of the number of the ionic oxygen scattering centers in the crystal lattice due to the
loss of oxygen ions at the interstitial sites.
3.5.彎曲的電氣性能的影響
彎曲的處理方法，噴霧 2.4和4.8莫耳％錫濃度的ITO塗層。研究在每次噴基板彎
曲過程削減到四個方面：
1.形成氣體（FG）治療，並再次測量。
2.受到拉伸彎曲，測量，FG治療，並再次測量。
3.遭到壓縮彎曲，測量，FG處理，並再次測量。
4.只熱不彎曲在相同加熱條件下（1.5小時 6508C）的情況下處理，測量，然後 FG
治療，並再次測量。顯示表電阻 RA LM噴溶液中含2.4莫耳％錫的樣品厚度的函
數，類似的行為已獲得 4.8 莫耳％的錫摻雜。 RA增加1.8提交壓縮彎曲層的因
素，並為提交拉伸彎曲層因素。在相同條件下加熱無彎曲顯示值之間的這些被調
查的大部分樣本的厚度。 FG治療結果所有四種類型的樣品，在強烈的RA下降。
有趣的是，要注意彎曲樣品兩種類型，表現出幾乎相同的結果低於直接從減少噴
狀態的扁平樣品的表電阻值降低治療後。厚度的彎曲和後續的治療效果減少約 5
± 7 LM VA值在280和430奈米之間。顯示了一個情節m與 n的圖的樣品。樣品已
受到同等待遇為一個圓形或橢圓形包圍。噴的樣品受到拉伸，彎曲以及6508C表
現出強烈的N和M減少，只有在加熱的樣本，而壓縮塗料只顯示 N.減少它認為，
在壓縮彎曲更緊密的聯繫和更高的陽離子發生在大致補償減少在加熱和拉伸彎
曲層檢測在M層的結晶顆粒之間的接觸面積。在N在所有情況下觀察到的減少可能
是由於非化學計量氧化物層 6508C的高溫氧化。在晶格中的氧空缺數目減少，這
個結果也可能越來越多多餘的氧原子位於晶格的間隙位置。這些多餘的氧原子帶
電導致離子的散射中心，減少在ITO LMS的流動性。隨後 FG處理逆轉這在一個
更高的氧氣 DE中的氧晶格效率比目前在初始狀態的影響和結果。因此ñ從 3:5
初始值1020 CM23英鎊上升至約 6英鎊 1020 CM23彎曲，只有加熱樣品。
3.6. Optical properties
Fig. 8 shows the as measured transmission and re¯ection curves for sprayed FTO coatings
with different thicknesses ranging from 175 to 1380 nm. The transmittance in the visible
region is signi®cantly lowered for thicker layers whereas the re¯ectance in the region
l . lp is increased
for thicker layers. The observed plasma-wavelength of all studied FTO coatings is lp
< 1:5 mm.
In Fig. 9 the optical properties of a 470 nm thick 2.4 mol.% Sn-doped ITO layer are shown
in the as-sprayed and reduced state. The transmittance is higher in the optical range
(<80%) than for an ATO coating with a comparable thickness (<72%). This indicates a lower
absorbance in the ITO layer than in the ATO ®lm. The steep increase in re¯ection begins
at l < 1:8 mm (plasma-wavelength) for the assprayed ITO coatings. A shift of the
re¯ectance onset of about 400 nm towards shorter wavelengths is observed for ITO coatings
after the FG treatment. The reason is an increase in n after the reduction treatment
which decreases the value of lp following the equation
and 1
0
where c0 is the velocity of light
the permittivity in vacuum, e is the elemental electron charge, 1
L
the relative
dielectric constant of the layer material, and meff is the effective mass of the free
electrons in the electrical conductive layer. A value of lp . 1.9 mm is obtained for
as-sprayed ITO layers by taking n . 3:2 £ 1020 cm23 and assuming that meff . 0.35 me and
1L . 3. A value lp . 1:3 mm is calculated for taking n . 6:5 £ 1020 cm23 for the reduced
state. These calculated values of 1.9 and 1.3 mm agree well with the values for lp
(estimated by the intersection of the slope of the re¯ection curves with the x-axis)
of 1.75 and 1.4 mm from Fig. 9. The observed values for the plasma-wavelength are nearly
independent from the thickness of the coating. The only difference in the optical
properties between the 470 nm thick and thinner ITO coatings is the height of the
transmission and re¯ection values for the same wavelengths. The onset in re¯ection at
shorter wavelengths for the reduced ITO samples also results in higher values in
re¯ection
for all wavelengths l . lp. Beyond l < 4 mm the IR re¯ection curves for the 470 nm thick
ITO coating in the assprayed and reduced state can not be distinguished from each other.
Both re¯ection curves reach a level of about 96% for l . 5 mm
3.6.光學特性
作為衡量傳輸噴 FTO導電塗料和不同，從 175到1380奈米不等厚度曲線。在可見
光區域的透射降低了，而重新在該地區升厚層。 LP是增加厚層。觀察到的所有
研究的FTO導電塗料等離子波長 LP <1:5毫米。而9470奈米厚2.4莫耳的Sn摻雜的
ITO層顯示在噴灑和減少的狀態的光學性質。透光率是在光範圍（<80％）高於類
似的厚度（<72％）ATO塗料。這表明在ITO層比在ATO LM低吸光度。在重新開始
急劇增加，在L <1時 08毫米（血漿波長）的ITO塗層。重新轉向約400奈米的對
波長有較短的觀察處理後的FGITO塗層。原因是在N的增加，從而降低LP值，下面
的方程，其中C0是光在真空中的介電常數和1 0的速度減少處理是元素的電荷，1
升的相對介電常數常數層材料，並是在導電層中的自由電子的有效質量。一個 LP
的價值。獲得 ITO層作為 n個噴霧1.9毫米。3:2英鎊 1020 CM23和假設。 0.35
和1L。A值LP。 n個 1:3毫米計算。 6:5英鎊減少狀態為 1020 CM23。這些計算
值的1.9和1.3毫米，同意為 LP值1.75和1.4毫米，等離子波長觀測值幾乎是從獨
立的塗層厚度。在470 nm厚的和更薄的ITO塗層之間的光學特性的唯一的區別是
相同的波長傳輸和重新估計值的高度。重新估計減少 ITO樣品在波長較短的發作
也導致重新估計值的增高
4. Conclusion
A comparison of the electrical and optical properties of spray pyrolyzed FTO, ATO and
ITO coatings has been especially after an optimized reduction treatment under forming
gas exhibit the best properties i.e. lowest electrical resistivity and highest optical
transmission. The reduced ITO layers show a resistivity of only 2.1±2:8 £ 1024 V cm which
is comparable to the resistivity of sputtered ITO coatings. The sprayed ITO layers show
an optical transmittance larger than 80% in the visible range. In comparison sprayed
ATO layers show poorest properties. Their resistivity is about 1 £ 1023V cm and their
transmittance is only <75% due to a stronger absorption in the ATO layers which also
shows a blackening tendency. The FTO layers produced by spraying with an ethanolic
solution of organic
monobutyltintrichloride show a low electrical resistivity of about 5 £ 1024 V cm and
high transmittance for thickness ,500 nm. Values of sheet resistances ,10 VA can be
reached for ®lm thicknesses of about 200 nm with reduced ITO coating or 500 nm as-sprayed
FTO, respectively. As-sprayed ITO coatings that are subjected to a bending process at
6508C show for tensile as well as for compressive bending treatment a strong increase
in sheet resistance independent of ®lm thickness. A forming gas treatment is able to
decrease these values by a factor of 4.5±7 to small values. These values are even lower
than those that are obtained by a direct forming gas treatment of the as-sprayed layers
without bending. For thicknesses of about 300 nm sheet resistance values of ,10 VA can
be obtained for both kinds of
bending process.
4.結論
在比較FTO .ATO 與ITO塗層，利用噴霧裂解法在平的與彎曲的玻璃基板上
，尤其是形成天然氣展覽，即最低的電阻率和最高的光學傳輸的最佳性能優化，
減少處理後。以降低ITO層顯示的只有2.1濺射電阻±2:8英鎊1024 V CM這是與電
阻率的ITO塗層。噴塗的ITO層的光透過率大於80％在可見光範圍內。相比之下，
噴霧ATO層顯示最小的屬性。它們的電阻率是約1萬英鎊1023V厘米，其透光率<75
％，由於在ATO層的一個較強的吸收，這也說明了一個發黑的趨勢。 FTO導電層
所產生的一個有機的乙醇溶液噴灑而顯示約 5低電阻英鎊1024 V CM厚度高透光
率，500奈米。表電阻值，10 VA可達到的LM厚度約 200奈米 ITO鍍膜減少或500
奈米噴霧FTO，分別由於噴塗的ITO6508C顯示在彎曲過程中受到的拉伸，壓縮彎
曲處理LM厚度的薄膜電阻獨立的強勁增長以及塗料。形成氣體治療能夠減少這些
值的4.5倍而±7值。這些值甚至比那些獲得直接噴層形成的氣體處理彎曲低。厚
度約300奈米的薄膜電阻值，10 VA可以得到兩種類型的彎曲的過程