Инд. авторы:	Yelisseyev A., Liang F., Isaenko L., Lobanov S.I., Goloshumova A.A, Lin Z.S.
Заглавие:	Optical properties of LiGaSe2 noncentrosymmetric crystal
Библ. ссылка:	Yelisseyev A., Liang F., Isaenko L., Lobanov S.I., Goloshumova A.A, Lin Z.S. Optical properties of LiGaSe2 noncentrosymmetric crystal // Optical Materials. - 2017. - Vol.72. - P.795-804. - ISSN 0925-3467. - EISSN 1873-1252.
Внешние системы:	DOI: 10.1016/j.optmat.2017.07.020; РИНЦ: 31065525; SCOPUS: 2-s2.0-85025137625;
Реферат:	eng: Large single crystals of LiGaSe2 were grown and their spectroscopic properties were studied. As-grown LiGaSe2 crystals are transparent in the 0.5–14 μm spectral region as well as at λ > 200 μm in the THz domain. A large blue shift of the fundamental absorption edge was established after high-temperature annealing in the presence of Li. Intense low-temperature photoluminescence (PL) in the 1.77 eV band is excited in the 3.0–3.6 eV absorption band near the fundamental absorption edge; PL intensity decreases by two orders of magnitude as temperature grows to 300 K. The X-ray irradiation results in crystal darkening, whereas the original state is restored after heating to 500 K or by visible light illumination. This effect is due to six traps that capture charge carriers: these traps were revealed using the thermoluminesence technique and their parameters were calculated. Pyroelectric luminescence in the 100–270 K range confirms the noncentrosymmetric structure of this crystal. DFT calculations were carried out to simulate the phonon density of states, optical absorption and Raman spectra. Calculations show that the intense 3.0–3.6 eV absorption band and corresponding 1.77 eV PL band may be associated with the cation antisite defects (GaLi), i.e. gallium in the Li site. The 2.15 and 2.4 eV emissions are likely due to the recombination of self-trapped excitons. © 2017 Elsevier B.V.
Ключевые слова:	Raman; Phonon density of state; Non-centrosymmetric crystals; Low temperature photoluminescence; LiGaSe2; Fundamental absorption edge; After high temperature; Structure (composition); Single crystals; Point defects; Optical properties; Luminescence; Light; Lithium alloys; Excitons; Excited states; Energy gap; Crystal structure; Binary alloys; Absorption; Structure; Raman; Luminescence; LiGaSe2; Band gap; Absorption; Gallium alloys; Spectroscopic property;
Издано:	2017
Физ. характеристика:	с.795-804