Properties of gallium selenide single crystal

We study the defect tetrahedral semiconductor Ga2Se3 with ordered vacant sites using state-of-the-art density-functional calculations The calculated main structural properties (the average cubic lattice parameter, a0=1020 au, and the average Ga–Se bond length, r=452 au) and electronic properties (the forbidden energy gap, direct, which amounts to about 24 eV) are in good agreement with the experimental data The role of the coordination defects is analyzed in detail, and the contribution of the different atoms to the electronic density of states is also discussed No significant differences are found if the vacant sites are ordered according to a monoclinic structure rather than orthorhombic, both previously proposed in literature, since the peculiar features of the structural and electronic properties are strongly related to the vacancies and their local environment rather than to their particular ordering We also discuss the results obtained for the orthorhombic phase pseudomorphically grown on

Structural and electronic properties of ga2se3

Optical properties of Ga2Se3 and Ga2Se3 :Co2+ single crystals

Our first-principles calculations show that the ordering of stoichiometric cation vacancies in Ga2Se3 has a large influence on the bandgap, up to 0.55 eV. Therein, the zigzag-line vacancy-ordered Ga2Se3 has the maximum bandgap (~2.56 eV direct bandgap), and the straight-line vacancy-ordered Ga2Se3 has the minimum bandgap (~1.99 eV indirect bandgap) at 0 K, according to scGW calculations. The bandgap difference (0.55 eV) is almost the same for normal density functional theory (DFT) calculations, hybrid DFT calculations and GW calculations. The calculation results are consistent with the experimental bandgap range of 2.0–2.6 eV at room temperature. Also, hydrostatic pressure (<9 GPa) tends to increase the bandgap, consistent with the experiments in the literature.

http://iopscience.iop.org/article/10.1088/0953-8984/25/22/225503/pdf

First-principles study of the structure and band structure of Ga2Se3.

Deep-acceptor levels associated with indium in indium-doped GaSe crystals have been measured. High-quality Schottky diodes of GaSe:In have been fabricated and characterized using current-voltage, capacitance-voltage, and deep-level transient spectroscopy (DLTS). Four DLTS peaks at 127, 160, 248, and 319K, corresponding to 0.21, 0.22, 0.44, and 0.74eV above the valence band, were well resolved and assigned to be an indium-on-gallium antisite (InGa), a gallium vacancy (VGa), an indium gallium vacancy complex (VGa-In), and a native defect associated with stacking fault or dislocation, respectively. Low-temperature photoluminescence (PL) spectroscopy measure-ments were performed on GaSe and GaSe:In crystals. The ground and the first excited states of the free exciton emissions were identified and the band-gap energies were determined. The results that the peak of exciton bound to acceptor (A0,X) disappeared and the peak of donor-acceptor pair appeared in GaSe crystal after indium doping are consistent with th...

https://scholarcommons.sc.edu/cgi/viewcontent.cgi?article=1193&context=elct_facpub

Byong-Hyuok Lee

Papers

Optical properties of Ga2Se3:Co2+ single crystals

Hole traps in GaSe:Co single crystals