10th Semester Presentation
27th April, 2023
Charge Transport in Organic-Inorganic
Heterostructure Devices
Chittadeepan Chakrabartty
1811053
Under Supervision of
Dr. Satyaprasad P. Senanayak
Dr. Saralasrita Mohanty
Nano-electronics and Device Physics Lab
School of Physical Sciences, NISER
Bhubaneswar-752050
1
Introduction
• Photo-induced charge carrier transport
– Traps and internal recombination
• Parameters
– Conductivity
– Responsivity
– Sensitivity
– Open-circuit voltage
– Short-circuit current
– Fill factor
– Efficiency
σ= (IxL)/(VxA)
R= (Iph – Idark)/Pinput
D= Rmin/Iph(min)
FF= (Vmax x Imax)/ (Voc x Isc)
η= (Vmax x Imax x 100)/(Pinput)
2
DOI:10.1002/adfm.202205398 , https://doi.org/10.1364/OE.426503 , 10.1002/9781118468586.epoc1028 , https://pubs.rsc.org/en/content/articlelanding/2020/tc/c9tc05695e
Introduction
• Heterostructure
ε= (aepitaxial - asubstrate)
aepitaxial
tcritical= asubstrate
2|ε|
• Types of heterostructure
Type I
Type II
Type III
Sze, S. M. Semiconductor Devices: Physics and Technology. New York: John Wiley and Sons, 1985
3
Introduction
• Inorganic semiconductor
• Organic semiconductor
 III-V binary semiconductor
 Mobility: ~102 -103 cm2 V-1s-1
P3HT
 Hydrocarbon conjugated
polymers
 Mobility: ~ 10-4 cm2/Vs
N2200
Gallium Phosphide
• Hybrid semiconductor
 3D Perovskites
 2D Perovskites
 Mobility: ~1-5 cm2/Vs
MAPbI3
(PEA)2SnBr4 , (PEA)2SnI4
DOI: https://www.researchgate.net/figure/ABX-3-perovskite-structure_fig2_323753234 , https://www.tcichemicals.com/US/en/c/12969, http://www.semiwafer.com/gap%20wafer.html,
https://pubs.acs.org/doi/pdf/10.1021/acsenergylett.7b00276, https://www.tandfonline.com/doi/full/10.1080/10601320701606711 , https://www.ioffe.ru/SVA/NSM/Semicond/GaP
4
Motivation: A blend of both worlds
Similar properties of Gallium Phosphide and Hybrid Perovskite
Large refractive index
High mobility and crystalline behaviour
Clean band structure
Moreover, it is advantageous to use hybrid perovskites to get different types of heterostructure
as they have readily tunable band gap due to high solution processibility at low temperature
DOI: https://www.cleanenergyauthority.com/solar-energy-news/organic-photovoltaic-solar-011521, https://www.energy.gov/eere/solar/multijunction-iii-v-photovoltaics-research, https://doi.org/10.1038/s41560-018-0125-0
5
Device Fabrication
Illumination
Illumination
25 nm
Al
P3HT
Perovskite
n-GaP on sapphire
Au 25 nm
100 nm
25 nm
250 nm
0.5 mm
Aluminium/n-GaP/p-Perovskite/P3HT/Gold
Experimental Device Architecture
• p-perovskite spin coated on one side of n-GaP
and annealed
• P3HT spin coated on top of p-perovskite layer
and annealed
• Gold thermally deposited on P3HT as top
electrode
• Aluminium thermally deposited on other side
of n-GaP as bottom electrode
Al
N2200
n-GaP on sapphire
Au 25 nm
100 nm
0.5 mm
Aluminium/n-GaP/N2200/Gold
Experimental Device Architecture
• N2200 spin coated on one side of n-GaP and
annealed
• Gold thermally deposited on N2200 as top
electrode
• Aluminium thermally deposited on other
side of n-GaP as bottom electrode
6
Fabricated Devices
Al/GaP/MAPbI3/Au
Al/GaP/(PEA)2SnI4/P3HT/Au
Al/GaP/(PEA)2SnI4/Au
Al/GaP/P3HT/Au
Al/GaP/MAPbI3/P3HT/Au
Al/GaP/(PEA)2SnBr4/P3HT/Au Al/GaP/N2200/Au
Al/GaP/(PEA)2SnBr4/Au
7
Analysis of photo-response characteristics
Pinput of device illumination= 10 mW/cm2
Area of device illumination= 0.045 cm2
Current-Voltage Characteristics
Current (A)
1.5
1.0
dark
Ag/GaP/(PEA)2SnI4/Au
Ag/GaP/P3HT/Au
Ag/GaP/N2200/Au
Al/GaP/MAPbI3/P3HT/Au
Al/GaP/MAPbI3/Au
Al/GaP/(PEA)2SnBr4/P3HT/Au
Ag/GaP/(PEA)2SnBr4/Au
Ag/GaP/(PEA)2SnI4/P3HT/Au
GaP/(PEA)2SnBr4 : Type II heterostructure
GaP/(PEA)2SnI4 : Type II heterostructure
GaP/MAPbI3 : Type I heterostructure
0.5
GaP/P3HT: Type II heterostructure
GaP/N2200: Type I heterostructure
0.0
-0.5
0.5
1.0
1.5
2.0
Voltage (V)
8
Analysis of GaP/Organic Polymer heterostucture
Area of device illumination= 0.045 cm2
Pinput of device illumination= 10 mW/cm2
Ag/GaP/P3HT/Au
Ag/GaP/N2200/Au
Light
Dark
30
- -
Current (nA)
- - - -
25
-3.8 eV
15
Au
10
-5.1 eV
5
N2200
-4.2 eV
n-GaP
hν
-5.4 eV
Light
Dark
-3.2 eV
- -
- -
-3.8 eV
Al
P3HT
45
n-GaP
Au
30
-5.1 eV
15
-5.2 eV
+ + + +
-4.2 eV
hν
+ + + +
0
-6.07 eV
0
0.5
1.0
1.5
2.0
-6.07 eV
+ + + +
0.0
0.5
Voltage (V)
1.0
Voltage (V)
σph= (3.54±0.15)E-10 mho/m
R= (7.080±0.009)E-05 A/W
Ag/GaP/P3HT/Au
Dark
Light
0.3
0.2
0.1
0.0
0.0
0.5
1.0
Voltage (V)
1.5
2.0
1.5
2.0
+ + + +
σph= (8.21±1.18)E-10 mho/m
R= (1.60±0.12)E-04 A/W
Ag/GaP/N2200/Au
Conductivity (n mho/m)
0.4
Conductivity (n mho/m)
- -
60
Al
-3.95 eV
20
- -
75
- -
Current (nA)
35
dark
light
0.8
•
Photo-conductivity increases at a slow rate
with increase in voltage without any
significant Voc due to very high internal
recombination
•
Photo-current
and
photo-conductivity
values for GaP/N2200 heterostructure are
lower than GaP/P3HT heterostructure as
both GaP and N2200 are n-type
0.6
0.4
0.2
0.0
0.5
1.0
Voltage (V)
1.5
2.0
9
DOI: https://public.wsu.edu/ pchemlab/documents/Work-functionvalues.pdf, https://www.ioffe.ru/SVA/NSM/Semicond/GaP, https://www.mdpi.com/2073-4360/10/2/121, 10.1016/j.orgel.2013.08.003
Analysis of GaP/2D Perovskite Type II Heterostructure
Ag/GaP/(PEA)2SnI4/P3HT/Au
Ag/GaP/(PEA)2SnI4/Au
0.9
Light
Dark
1.2
Dark
Light
Current (A)
Current (A)
0.9
0.6
0.3
0.0
0.3
Pinput of device
illumination
Area of device
illumination
0.0
10 mW/cm2
0.045 cm2
0.6
-0.3
-0.3
0.0
0.5
1.0
1.5
0.5
2.0
Voltage (V)
- -
-3.2 eV
- -
-3.7 eV
1.0
Voltage (V)
- - - -
n-GaP
-5.6 eV
+ + + +
- -
2.0
-6.07 eV
+ + + +
-4.2 eV
hν
Al
-3.8 eV
(PEA)2SnI4
n-GaP
Au
-5.1 eV
-5.2 eV
•
Photo-conductivity and responsivity
increases with extra P3HT layer on
perovskite than that without P3HT as
P3HT blocks electron transport and
permits holes
•
Photo-conductivity and responsivity
are
very
low
in
GaP/P3HT
heterostructure as GaP is only
inorganic and P3HT is only organic
- -
Al
P3HT
(PEA)2SnI4
-5.1 eV
- -
-3.7 eV
-3.8 eV
Au
- -
1.5
-5.6 eV
+ + + +
-6.07 eV
+ + + +
-4.2 eV
hν
10
Doi: https://public.wsu.edu/ pchemlab/documents/Work-functionvalues.pdf, https://www.ioffe.ru/SVA/NSM/Semicond/GaP, https://www.mdpi.com/2073-4360/10/2/121, https://pubs.acs.org/doi/10.1021/acsenergylett.7b00414
Analysis of GaP/2D Perovskite Type II Heterostructure
Area of device illumination= 0.045 cm2
Pinput of device illumination= 10 mW/cm2
Sl.
No
Device Structure
Photo-conductive regime
Photo-voltaic regime
σdark
(x10-8
mho/m)
σph
(x10-8
mho/m)
R
(x10-3
A/W)
Voc
(V)
Jsc
(μA/
cm2)
FF
η
(x10-3 %)
1
Al/GaP/(PEA)2SnI4/P3HT/Au
0.011
5.65
±0.06
2.82
±0.27
0.8
±0.1
3.355
±0.05
0.336
8.93
±2.40
2.
Al/GaP/(PEA)2SnI4/Au
0.115
4.26
±0.14
2.13
±0.05
0.6
±0.1
5.934
±0.09
0.216
7.73
±2.59
3.
Al/GaP/P3HT/Au
0.002
0.08
±0.01
0.16
±0.01
0.0
0.000
0.000
0.000
• Photo-conductivity increases by ~1.8 x 10-8 mho/m and responsivity increases by ~0.7 x 10-3 A/W with additional P3HT
over (PEA)2SnI4 than that of only (PEA)2SnI4
• Photo-conductivity becomes nearly 50 times and responsivity becomes roughly 12.5 times on using (PEA)2SnI4 only on
Gallium Phosphide as compared to P3HT only on Gallium Phosphide
• Conductivity increases maximally by 513 times from dark to full illumination for Al/GaP/(PEA)2SnI4/P3HT/Au
11
Analysis of GaP/2D Perovskite Type II Heterostructure
60
Al/GaP/(PEA)2SnBr4/P3HT/Au
Ag/GaP/(PEA)2SnBr4/Au
0.20
Current (A)
Current (nA)
45
30
15
0.15
0.10
0.05
0.5
1.0
1.5
0.0
2.0
0.5
Area of device
illumination
10 mW/cm2
0.045 cm2
- -
- -
- -
-2.8 eV
- -
(PEA)2SnBr4
n-GaP
Au
-3.2 eV
- -
-3.8 eV
-6.07 eV
+ + + +
1.5
2.0
- -
-2.8 eV
- -
P3HT
-4.2 eV
(PEA)2SnBr4
n-GaP
Au
-5.1 eV
-5.2 eV
Photo-conductivity
and
responsivity
increases with extra P3HT layer on
perovskite than that without P3HT as P3HT
blocks electron transport and permits holes
•
There is significant rise in photoconductivity for GaP/(PEA)2SnBr4 than
GaP/P3HT as GaP is only inorganic and
P3HT is only organic
Al
-4.2 eV
hν
-5.5 eV
+ + + +
-6.07 eV
+ +
•
- -
-3.8 eV
Al
hν
-5.5 eV
+ + + +
1.0
Voltage (V)
Voltage (V)
-5.1 eV
Pinput of device
illumination
0.00
0
0.0
Light
Dark
0.25
Light
Dark
+ +
12
Doi: https://public.wsu.edu/ pchemlab/documents/Work-functionvalues.pdf, https://www.ioffe.ru/SVA/NSM/Semicond/GaP, https://www.mdpi.com/2073-4360/10/2/121, https://pubs.rsc.org/en/content/articlelanding/2020/TC/D0TC02525A
Analysis of GaP/2D Perovskite Type II Heterostructure
Pinput of device illumination= 10 mW/cm2
Sl.
No
Device Structure
1.
Area of device illumination= 0.045 cm2
Photo-conductive regime
Photo-voltaic regime
σdark
(x10-8
mho/m)
σph
(x10-8
mho/m)
R
(x10-3
A/W)
Voc
(V)
Jsc
(μA/
cm2)
FF
η
(x10-4 %)
Al/GaP/(PEA)2SnBr4/P3HT/Au
0.007
1.02
±0.23
0.51
±0.01
1.1
±0.1
0.133
±0.03
0.335
4.9±1.16
2.
Al/GaP/(PEA)2SnBr4/Au
0.006
0.18
±0.006
0.12
±0.02
0.7
±0.1
0.222
±0.08
0.183
2.87±0.72
3.
Al/GaP/P3HT/Au
0.002
0.08
±0.01
0.16
±0.01
0.0
0.000
0.000
0.000
• Photo-conductivity increases by ~0.8 x 10-8 mho/m and responsivity increases by ~0.4 x 10-3 A/W with additional P3HT
over (PEA)2SnBr4 than that of only (PEA)2SnBr4
• Photo-conductivity becomes nearly 2 times on using (PEA)2SnBr4 only on Gallium Phosphide as compared to P3HT only
on Gallium Phosphide
• Conductivity increases maximally by 145 times from dark to full illumination for Al/GaP/(PEA)2SnBr4/P3HT/Au
13
Analysis of GaP/3D perovskite heterostructure
Al/GaP/MAPbI3/Au
0.6
Al/GaP/MAPbI3/P3HT/Au
Light
Dark
Light
Dark
1.5
0.5
Pinput of device
illumination
Area of device
illumination
0.0
10 mW/cm2
0.045 cm2
1.0
Current (A)
Current (A)
0.4
0.2
0.0
-0.2
-0.5
-0.4
0.0
0.5
1.0
Voltage (V)
- - -
- -
1.5
0.0
2.0
0.5
-3.2 eV
- -
-3.8 eV
Au
-5.1 eV
n-GaP
-5.7 eV
+ + + +
-6.07 eV
+ + + +
-4.2 eV
hν
P3HT
Al
- -
-5.2 eV
2.0
-3.8 eV
Photo-conductivity and responsivity
increases with extra P3HT layer on
perovskite than that without P3HT as
P3HT blocks electron transport and
permits holes
•
Photo-conductivity and responsivity are
very low in GaP/P3HT heterostructure as
GaP is only inorganic and P3HT is only
organic semiconductor
Al
-4.1 eV
-5.7 eV
•
- -
-4.2 eV
MAPbI3
Au
-5.1 eV
1.5
- - -
-4.1 eV
MAPbI3
1.0
Voltage (V)
n-GaP
+ + + +
-6.07 eV
+ + + +
hν
14
Doi: https://public.wsu.edu/ pchemlab/documents/Work-functionvalues.pdf, https://www.ioffe.ru/SVA/NSM/Semicond/GaP, https://www.mdpi.com/2073-4360/10/2/121, https://arxiv.org/pdf/1402.4980
Analysis of GaP/3D Perovskite Heterostructure
Pinput of device illumination= 10 mW/cm2
Sl.
No
Device Structure
1
Area of device illumination= 0.045 cm2
Photo-conductive regime
R
(x10-3
A/W)
Photo-voltaic regime
σdark
(x10-8
mho/m)
σph
(x10-8
mho/m)
Voc
(V)
Al/GaP/MAPbI3/P3HT/Au
0.005
6.89
±0.19
3.44 1.2 8.844 0.484
±0.84 ±0.1 ±0.04
0.051
±0.009
2
Al/GaP/MAPbI3/Au
0.003
1.67
±0.44
1.11 1.5 9.467 0.473
±0.26 ±0.1 ±0.08
0.067
±0.016
3.
Al/GaP/P3HT/Au
0.002
0.08
±0.01
0.16
±0.01
0.000
0.0
Jsc
(μA/
cm2)
FF
0.000 0.000
η (%)
• Photo-conductivity increases by ~5.2 x 10-8 mho/m (becomes more than 4 times) and responsivity increases
by ~2.33 x 10-3 A/W (becomes more than 3 times) with additional P3HT over MAPbI3 than that of only MAPbI3
• Photo-conductivity becomes nearly 20 times and responsivity becomes roughly 7 times on using MAPbI3 only
on Gallium Phosphide as compared to P3HT only on Gallium Phosphide
• Conductivity increases maximally by 1378 times from dark to full illumination for Al/GaP/MAPbI3/P3HT/Au
15
Analysis of photo-voltaic characteristics
Area of device illumination= 0.045 cm2
Pinput of device illumination= 10 mW/cm2
0.4
0.2
Conductivity-Voltage Characteristics
0.450
dark
Al/GaP/MAPbI3/P3HT/Au
Al/GaP/MAPbI3/Au
Ag/GaP/(PEA)2SnI4/Au
Ag/GaP/P3HT/Au
Ag/GaP/N2200/Au
Ag/GaP/(PEA)2SnI4/P3HT/Au
Al/GaP/(PEA)2SnBr4/P3HT/Au
Ag/GaP/(PEA)2SnBr4/Au
0.375
Power (W)
Conductivity (mho/m)
0.6
0.0
Ag/GaP/(PEA)2SnI4/Au
Al/GaP/MAPbI3/P3HT/Au
Al/GaP/MAPbI3/Au
Al/GaP/(PEA)2SnBr4/P3HT/Au
Ag/GaP/(PEA)2SnI4/P3HT/Au
Ag/GaP/(PEA)2SnBr4/Au
0.225
0.150
0.075
-0.2
-0.4
0.300
Power-Voltage Characteristics
0.000
0.5
1.0
Voltage (V)
1.5
2.0
0.5
1.0
1.5
Voltage (V)
16
Analysis of photo-voltaic characteristics
0.5
Al/GaP/MAPbI3/P3HT/Au
0.300
0.15
0.225
0.10
0.150
0.05
0.075
0.2
0.4
0.6
0.8
1.0
- -
- -
- -
-3.8 eV
Al
-4.1 eV
-4.2 eV
MAPbI3
Au
-5.1 eV
-5.7 eV n-GaP
-5.2 eV
0.00
0.0
- -
P3HT
0.20
Power (W)
Current (A)
0.375
-3.2 eV
0.25
hν
+ + + +
0.28
0.3
0.21
0.2
0.14
0.1
0.07
Jsc= (8.84± 0.04) µA/cm2
Voc= (1.2± 0.1) V
FF= 0.484
η= 0.051±0.009 %
Al/GaP/MAPbI3/Au
0.075
Conductivity ( mho/m)
Conductivity ( mho/m)
0.1
0.0
0.0
0.5
1.0
Voltage (V)
1.5
2.0
MAPbI3
-5.7 eV
+ + + +
-4.2 eV
n-GaP
-6.07 eV
hν
+ + + +
•
Photo-current decreases from maximum
value at 0 V and diminishes at Voc
•
Output power increases from 0V, then
reaches a maximum value at optimal
voltage and then diminishes at Voc
0.000
-0.225
-0.3
Au
-5.1 eV
Al
Photo-conductivity increases drastically
with increase in voltage till Voc and then
increases at a much slower rate
-0.150
-0.2
-3.8 eV
-4.1 eV
•
dark
light
-0.075
-0.1
- -
- -
Jsc= (9.46± 0.08) µA/cm2
Voc= (1.5± 0.1) V
FF= 0.473
η= 0.067±0.016 %
Al/GaP/MAPbI3/P3HT/Au
dark
light
- -
0.4
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Voltage (V)
-6.07 eV
Voltage (V)
- -
0.35
0.00
+ + + +
1.2
Current
Power
Power (W)
0.450
Current (A)
Current
Power
Al/GaP/MAPbI3/Au
0.0
0.5
1.0
Voltage (V)
1.5
2.0
Doi: https://public.wsu.edu/ pchemlab/documents/Work-functionvalues.pdf, https://www.ioffe.ru/SVA/NSM/Semicond/GaP, https://www.mdpi.com/2073-4360/10/2/121, https://arxiv.org/pdf/1402.4980
17
Analysis of device with maximum photo-response
Area of device illumination= 0.045 cm2
Al/GaP/MAPbI3/P3HT/Au
30
Current-Voltage Characteristics
0 sun
0.02 sun
0.04 sun
0.06 sun
0.08 sun
0.1 sun
1.0
0.8
0.6
20
0.4
Current (nA)
Current ()
0.4
Max Photocurrent ()
Responsivity Characteristics
0.8
0.2
0.0
0
2
4
6
8
10
Input Light Intensity (mW/cm2)
0.0
10
Power-Voltage Characteristics
8
Power (nW)
Current-Voltage Characteristics
10
6
0.02 sun
0.04 sun
0.06 sun
0.08 sun
0.1 sun
4
2
-0.4
0.5
1.0
Voltage (V)
1.5
0
0.0
2.0
Photo-voltaic characteristics
0.6
Jsc
Voc
0.5
0.4
0.8
0.6
0.3
0.4
0.2
0.1
0.2
0.0
0
2
4
6
0.2
0.4
0.6
0.0
0.8
Voltage (V)
8
Input Illumination Intensity
10
0.0
Open Circuit Voltage (Voc) (V)
Short Circuit Current (Jsc) (A/cm2)
0.0
0.2
0.4
0.6
0.8
Voltage (V)
Parameters
at 0.1 sun
Value
Voc
0.83 V
Jsc
0.44 µA/cm2
FF
0.32
σ
10.31E-08 mho/m
R
6.5E-09 A/W
D
0.0102 W-1
η
0.002%
•
•
•
Photo-current decreases with decrease in
light intensity in photo-conductive regime
due to less formation of exciton pair.
Responsivity doesn’t increase linearly with
increase in illumination intensity.
In photo-voltaic regime, photo-current and
output power don’t exactly follow the rise
in voltage. Jsc and Voc don’t exhibit an
increasing trend with increase in light
intensity.
18
Conclusion
• GaP with MAPbI3 in the presence of P3HT forms effective heterostructure photo-detectors
due to better device performance as compared to other perovskites evident from
(6.89±0.19)E-08 mho/m photo-conductivity, 0.0102 W-1 sensitivity and (1.11±0.26)E-03
A/W responsivity values
• P3HT acts as an effective hole transport layer for n-GaP/p-Perovskite heterostructure
(except (PEA)2SnBr4 where it acts only as a buffer between metal and semiconductor) as
evident from its band gap orientation and photo-conductivity values of devices
• Power extracted from PV devices exhibits an optimal behavior due to optimal extraction of
charge carriers and hence needs to be used at optimal operating voltage evident from
power-voltage characteristics
• GaP forms better heterostructure solar cells with 3D perovskites (i.e MAPbI3) as evident
from Jsc= (9.46± 0.08) µA/cm2, Voc= (1.5± 0.1) V, Fill Factor= 0.473 and η= 0.067±0.016 % as
compared to 2D perovskites ((PEA)2SnI4, (PEA)2SnBr4)
19
Future Work: GaP/3D Perovskite Type II Heterostructure
•
Al/GaP/MAPbBr3/P3HT/Au
•
e e
e e
-3.6 eV
P3HT
e e
e e
-3.8 eV
MAPbBr3
Au
-5.1 eV
-5.2 eV
-5.9 eV
Al
-4.2 eV
n-GaP
•
hν
h h h h
Capacitance-Voltage Characteristics
-6.07 eV
25nm Al
P3HT
MAPbBr3
n-GaP on sapphire
Illumination
Experimental Device Structure
Au 25nm
100 nm
250 nm
0.5 mm
Capacitance (nF)
h h h h
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
0 sun
0.02 sun
0.04 sun
0.06 sun
0.08 sun
0.1 sun
Capacitance-Frequency Characteristics
0 sun
0.02 sun
0.04 sun
0.06 sun
0.08 sun
0.1 sun
3.00
2.25
Capacitance (nF)
-3.2 eV
Fabrication and characterization of Al/GaP/MAPbBr3/P3HT/Au and Al/GaP/MAPbBr3/Au
devices to confirm the role of exciton dissociation since MAPbBr3 is a p-type 3D perovskite,
has high dielectric constant (low exciton dissociation energy) and forms Type II (instead of
Type I) heterostructure.
It has been observed that capacitance of the devices increase with increase in light intensity
and attains a peak value with change in voltage. Also, capacitance decreases with increase in
frequency and cut-off frequency increases with decrease in light intensity. Further
investigation and research work is necessary to find the cause of this observed phenomena
and correlate it Trap DOS using Mott-Schottky plot.
Determination of strain parameter at the organic-inorganic heterojunction for different
devices and correlate it to device performance.
1.50
0.75
0.00
-2
-1
0
1
Voltage (V)
2
1
10
100
Frequency (kHz)
1000
Doi: https://public.wsu.edu/ pchemlab/documents/Work-functionvalues.pdf, https://www.ioffe.ru/SVA/NSM/Semicond/GaP, https://www.mdpi.com/2073-4360/10/2/121, https://www.mdpi.com/1996-1944/9/9/747
20
Acknowledgements
• I would like to thank my supervisors Dr. Satyaprasad P. Senanayak and Dr.
Saralasrita Mohanty and other lab members of Nano-electronics and Device
Physics Lab (NDPL), my fellow batchmates, my seniors for their guidance
and help.
• Besides, Dr. Shovon Pal and his students contributed in completing the
project.
• I also acknowledge the DAE funding for pursuing experiments at NDPL, CIF
labs, SPS, NISER and KVPY-INSPIRE for monthly fellowship.
21
Thank You
22