Trends in the band-gap pressure coefficients and bulk moduli in different structures of ZnGa₂S₄, ZnGa₂Se₄and ZnGa₂Te₄

Abstract

We have performed a first-principles investigation for the family of compounds ZnGa 2 X 4 (X = S, Se, Te). The properties of two possible structures, defect chalcopyrite and defect famatinite are both calculated. We reveal that ZnGa 2 S 4 and ZnGa 2 Se 4 have direct band gaps, while ZnGa 2 Te 4 has an indirect band gap. The local density approximation band gaps are found to be very different in two structures, while the lattice parameters and bulk moduli are similar. We extend Cohen's empirical formula for zinc-blende compounds to this family of compounds. The pressure coefficients are calculated and metallization pressures are discussed. We find that a i g remains fairly constant when the group-V I element X is varied in ZnGa 2 X 4 (II-III 2 -VI 4 ).

Bulk Modulus, Elastic Constants, and Force Constants of Interatomic Bonds of II–III2–VI4 Compounds

“…All E symmetry modes are doubly degenerated; one B mode and one E mode are acoustic. All optical modes (3A, 5B, and 5E) are 39 [36] 40 [37] Raman active (R). In the infrared absorption (IR) spectra, allowed in polarization parallel to the tetragonal C axis 5B symmetry modes and 5 doubly degenerated E symmetry modes are active.…”

Impedance Spectroscopy of Nanostructure p-ZnGa2Se4/n-Si Heterojunction Diode

“…The low packing efficiency of constituent atoms in lattice facilitates the doping of these compounds by impurities [1,3]. These ordered vacancy compounds form a bridge between impurity physics and crystal physics [4]. They are a class of materials with high technological interest due to their semiconducting properties, broad band gaps, high optical strength, high photosensitivity and intense luminescence, and potential applications in linear, nonlinear optical and photovoltaic devices [1,2,4].…”

“…These ordered vacancy compounds form a bridge between impurity physics and crystal physics [4]. They are a class of materials with high technological interest due to their semiconducting properties, broad band gaps, high optical strength, high photosensitivity and intense luminescence, and potential applications in linear, nonlinear optical and photovoltaic devices [1,2,4]. In particular, HgGa 2 S 4 and Cd 1−x Hg x Ga 2 S 4 are widely used as nonlinear optical materials [5].…”

“…In particular, HgGa 2 S 4 and Cd 1−x Hg x Ga 2 S 4 are widely used as nonlinear optical materials [5]. Also, tunable filters based on CdGa 2 S 4 and UV photodetectors based on CdAl 2 S 4 are already used as devices [4]. ZnGa 2 Se 4 which is one of these defect chalcopyrite ordered vacancy compounds is a photosensitive material [5].…”