Title :
Photoluminescence and X-ray analysis of laser deposited II-VI thin films and multilayered structures
Author :
Perna, G. ; Ambrico, M. ; Smaldone, D. ; Martino, R. ; Capozzi, V. ; Lorusso, G. ; Giardini, A. ; Mele, A.
Author_Institution :
CNR, Tito Scalo, Italy
Abstract :
This work aims to determine the best buffer layer for the deposition of II-VI heterostructures on silicon. The results obtained from laser ablated films (1 μm thick) of CdSe, CdS and CdTe at different substrate temperatures are presented. A Nd:YaG laser (λ=532 nm) was used to ablate and deposit II-VI compounds in a vacuum chamber pumped down to 10/sup -6/ Torr. X-ray spectra were analysed and grain dimensions were calculated accordingly to Debye Sherrer formula. Photoluminescence experiments were carried out to study radiative transition and emission efficiency of the laser ablated films. A detailed study of linewidth and spectral position of the exciton line versus temperature T was performed. Broad PL bands due to extrinsic luminescence are present both in CdS and CdSe films. This PL feature is related to impurity levels localized in the energy gaps of the films. Recombination of donor acceptor pairs occurs and they are studied as a function of T and laser power.
Keywords :
II-VI semiconductors; X-ray diffraction; cadmium compounds; excitons; impurity states; photoluminescence; pulsed laser deposition; semiconductor growth; semiconductor heterojunctions; semiconductor thin films; spectral line breadth; CdS; CdSe; CdTe; Debye Sherrer formula; Si; X-ray diffraction; buffer layer; donor acceptor pairs; emission efficiency; exciton line; grain dimensions; impurity levels; laser ablated films; laser power; multilayered structures; photoluminescence; radiative transition; substrate temperature; thin films; Buffer layers; Excitons; Laser excitation; Laser transitions; Luminescence; Photoluminescence; Pump lasers; Silicon; Temperature; X-ray lasers;
Conference_Titel :
Advanced Applications of Lasers in Materials Processing/Broadband Optical Networks/Smart Pixels/Optical MEMs and Their Applications. IEEE/LEOS 1996 Summer Topical Meetings:
Conference_Location :
Keystone, CO, USA
Print_ISBN :
0-7803-3175-3
DOI :
10.1109/LEOSST.1996.540661
