1 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA.

2 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA. Study of Photoluminescence properties of Sea-Urchin like CdS nanostructures prepared by CVD method. Bader Al Salman Presented by: Bader Al Salman Faculty of Physics Department Presented to: Faculty of Physics Department May 11, 2015/ Rajab 22, 1436 Date: May 11, 2015/ Rajab 22, 1436

3 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA. Contents Section No. 1Abstract Section No. 2 Introduction Section No. 3Methods & Materials Section No. 4Results & Conclusions

Abstract 4 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA.  In this work, we use chemical vapor deposition (CVD) technique to synthesize CdS 1 D-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.

Introduction 5 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA. CdS has been extensively used in electronic and optoelectronic materials with prominent high- technology applications include LEDs, lasers, sensors, etc as shown in Figure. NameCadmium(II) Sulfide Molecular formula CdS PhaseSolid ColorYellow GroupII–VI Crystal structure Hexagonal Band gap2.42 eV or 512 nm

Methods 6 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA. Chemical vapor deposition (CVD) Synthesis technique: Chemical vapor deposition (CVD) 1g CdS powder: 1g 750 °C Heating temperature: 750 °C 30 min Constant Time: 30 min Ar Carrier Gas: Ar

Results 1) Morphology & Emission Images 2) XRD 3) PL 7 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA.

Morphology & Emission Images 8 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA. Figure (a) low magnification bright field image of CdS nanobelts, and (b) corresponding emission image under 325 nm laser excitation. (c) low magnification bright field image of Sea-Urchin like CdS nanostructures, (d) individual Sea-Urchin like CdS nanostructure, and (f) corresponding emission image under the same excitation source.

XRD Results 9 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA. (a) XRD pattern of CdS nanobelts. (b) of Sea-Urchin like CdS nanostructures. XRD pattern concludes Hexagonal structure.

Photoluminescence (PL) 10 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA. (a) PL spectrum of CdS nanobelts. (b) of Sea-Urchin like CdS nanostructures. Excitation source is 325 nm laser. Result: PL identified easily defects level in the nanostructures.

Conclusion 11 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA.  PL of sea-urchin-like CdS nanostructures 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 technique help us to identify Defects exist in the nanostructures.

Acknowledgement 12 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA.  I am Thankful to Dr-Thamer Al Harbi (HOD of Physics Department) for providing me experimental facilities.  My deepest thank to Mr. Muhammad Al Bedah & Mr. Raed Al Faleh for helping me in English/Arabic translation.  Special thanks to Dr-Mohammad Abushayeb & Prof. Abdul Majid for their support and help.

13 Materials Science Laboratory, Department of Physics, College of Science, Az Zulfi, Majmaah University, KSA. Thanks for your attention