Low-temperature photoluminescence study of GaS0.5Se0.5 layered crystals
Author
Aydnl, A.
Gasanly, N. M.
Gökşen, K.
Date
2001Source Title
Materials Research Bulletin
Print ISSN
0025-5408
Publisher
Elsevier Science
Volume
36
Issue
10
Pages
1823 - 1832
Language
English
Type
ArticleItem Usage Stats
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Abstract
Photoluminescence (PL) spectra of GaS0.5Se0.5 layered single crystals have been studied in the wavelength range of 565-860 nm and in the temperature range of 15-170 K. Two PL bands centered at 585 nm (2.120 eV) and 640 nm (1.938 eV) were observed at T = 15 K. Variations of both bands were studied as a function of excitation laser intensity in the range from 10-3 to 15.9 W cm-2. These bands are attributed to recombination of charge carriers through donor-acceptor pairs located in the band gap. Radiative transitions from shallow donor levels located at 0.029 and 0.040 eV below the bottom of the conduction band to deep acceptor levels located 0.185 and 0.356 eV above the top of the valence band are suggested to be responsible for the observed A- and B-bands in the PL spectra, respectively. A simple energy level diagram explaining the recombination process is proposed.
Keywords
A. ChalcogenidesA. Semiconductors
D. Luminescence
D. Optical Properties
Charge carriers
Optical properties
Photoluminescence
Single crystals
Chalcogenides
Gallium sulfur selenide
Semiconducting gallium compounds