Study of Photoluminescence properties of Sea-Urchin
like CdS nanostructures prepared by CVD method.
Bader al Salman, Muhammad Arshad Kamran
Physics Department, College of Science Al-Zulfi
Majmaah University, KSA.
Abstract
In this work, we use chemical vapor deposition (CVD) technique to synthesize CdS 1D-nanostructures (nanobelts & Sea-Urchin like nanostructures). The
morphological characterizations of the product were examined by optical microscope, while optical properties are investigated by Photoluminescence (PL)
spectroscopy. PL spectroscopy helps to identify the crystallinity of the nanostructures. Those structures show only bandedge (BE) emission confirm the highest
crystalline quality whereas some structures show broad band emission near 2.06 eV along with the BE emission indicating that some defects are involved like
surface states.
Introduction
•No doubt, semiconductors are the most admirable discovery of modern world. Semiconductors are
materials with controllable charge carriers. This unique feature leads to the discovery of transistors and
diodes which serve as building blocks of semiconductor devices for modern-electronics. Mankind would not
have entered the era of highly developed information technology (IT) if semiconductor was not invented.
Cathodoluminescence
Lasers
Photovolatics
LED’s
Photochemistry
•Silicon (Si) and GaAs are the pioneers of semiconductor group. These traditional semiconductors have been
Waveguides
replaced by another class of semi-conductor materials, known as group II-VI sulfides (CdS).
•Among II-VI sulfides, CdS has been extensively used in electronic and optoelectronic materials with
prominent high-technology applications include LEDs, lasers, sensors, photodetectors, optical waveguides etc
as shown in Figure. In this work, we studied the PL properties of Sea-Urchin like CdS nanostructure.
Gas sensors
Field emitters
FETs
Photodetectors
Methods & Materials
A horizontal tube furnace (HTF) was used for the growth of 1D-CdS nanobelts. 1 g CdS powder (99.995%, Aldrich) was loaded into a ceramic boat and placed at
the centre of HTF. A silicon substrate was placed at appropriate distance away from the source material. HTF was pumped with rotary pump and purged with
highly pure Ar gas (99.99%) for 15–20 min. Gas (Ar) flow for the reaction was adjusted to 60 sccm (standard cubic centimeter per minute) and ramp rate was
chosen to be 70°C /min. The temperature was raised to 750 °C and was held at that temperature for 30 minutes before returning to room temperature. The
system was allowed to cool down naturally. After the reaction, a light yellow colored product was obtained on the Si substrates. For the synthesis of 1D-CdS SeaUrchin like nanostructures, all conditions were kept same except Si substrate kept upside down.
Growth
Setup
High-quality sea-urchin-like CdS nanostructures were successfully fabricated via
CVD method. XRD pattern shows the as synthesized CdS nanostructures have
wurtzite structure. PL measurements show only bandedge emission at 512 nm,
which means our sea-urchin-like CdS nanostructures posses high quality optical
property. These results are important in the design of future green luminescence,
and display devices.
PL of CdS belts
PL of CdS Sea-Urchin
Sea-Urchin
CdS Sea-Urchin
CdS Sea Urchin
XRD Pattern
Conclusion
Emission Image
Emission Image CdS belts
XRD Pattern
Results
Defect-level
Emission
Band-Edge
Emission
Acknowledgements
The authors thank the Head of Physics Department for providing experimental
facilities and support for Scientific Research.
Bader Al Salman