Bader Al - PowerPoint Presentation

Slide1

Bader Al

Salman

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.

Silicon (Si) and

GaAs

are the pioneers of semiconductor group. These traditional semiconductors have been replaced by another class of semi-conductor materials, known as group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.

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 Sea-Urchin like nanostructures, all conditions were kept same except Si substrate kept upside down.

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.

Conclusion

Acknowledgements

The authors thank the Head of Physics Department for providing experimental facilities and support for Scientific Research.

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.

Emission Image

CdS belts

Growth Setup

Sea-Urchin

CdS Sea Urchin

Results

Band-Edge

Emission

Defect-level

Emission

Photochemistry

Photovolatics

Cathodoluminescence

Lasers

LED’s

Waveguides

Field emitters

FETs

Photodetectors

Gas sensors

XRD Pattern

XRD Pattern

Emission Image

PL of CdS belts

PL of CdS Sea-Urchin

CdS Sea-Urchin