The Study of Optical Properties of III₂–VI₃ Defect Semiconductor Group Compounds Ga₂S₃, Ga₂Se₃, In₂S₃, and In₂Se₃

Abstract

Herein, high‐quality III2VI3 (III = Ga, In and VI = S, Se) single crystals are successfully grown by a chemical vapor transport method. X‐ray diffraction and Raman spectroscopy verify crystal structure, crystalline state, and vibration modes of the as‐grown III2VI3 crystals. According to the structure characterization, Ga2S3 is crystallized in a monoclinic structure, whereas Ga2Se3 belongs to the cubic zincblende phase. The crystal structure of In2S3 is tetragonal, whereas that of In2Se3 may come from a hexagonal layered structure. The four crystal structures are the most stable phases crystallized in Ga2S3, Ga2Se3, In2S3, and In2Se3, respectively. All the mostly stable phase in each of Ga2S3, Ga2Se3, In2S3, and In2Se3 is different and changing. This result identifies the crystalline nature of the III–VI group defect crystals. Modulated thermoreflectance (TR) and optical transmission measurements of the series III2VI3 compounds are, respectively, implemented. The results indicate that all defective Ga2S3, Ga2Se3, In2S3, and In2Se3 crystals are direct semiconductors. Photoluminescence of Ga2S3 and photoconductivity of the Ga2Se3, In2S3, and In2Se3 defect compounds are, respectively, carried out, and the experimental results are demonstrated and analyzed herein.

Thin Ga2O3 Layers by Thermal Oxidation of van der Waals GaSe Nanostructures for Ultraviolet Photon Sensing

“…In the pristine layers, the A 1 1g , E 1 2g and A 2 1g peaks of GaSe are observed at 132 cm –1 , 206 and 308 cm –1 , respectively, as reported for the centrosymmetric (D 3d ) polymorph of GaSe . The annealing at T a = 400 °C produces additional peaks at 156 and 293 cm –1 , suggesting partial conversion of the GaSe layers into Ga 2 Se 3 . Increasing the annealing temperature to T a = 500 °C promotes a full conversion of GaSe into Ga 2 Se 3 , as indicated by the vanishing intensity of the GaSe modes.…”

“…12 The annealing at T a = 400 °C produces additional peaks at 156 and 293 cm −1 , suggesting partial conversion of the GaSe layers into Ga 2 Se 3 . 38 Increasing the annealing temperature to T a = 500 °C promotes a full conversion of GaSe into Ga 2 Se 3 , as indicated by the vanishing intensity of the GaSe modes. At T a = 600 °C, only the Raman modes for crystalline (237 cm −1 ) and amorphous-Se (250 cm −1 ) are observed, suggesting that the GaSe layer fully converts into an amorphous oxide.…”

2D hexagonal CuGaSe2 nanosheets by a microwave assisted synthesis method: photoresponse and optical study for optoelectronic applications

“…The observed bandgap value is also lower than individual Cu 2 Se (∼1.9 eV) 49 and Ga 2 Se 3 (∼1.85 eV) bandgaps. 50 The variation of E g with respect to irradiation is shown in Fig. 8(c).…”

Review of Nanolayered Post-transition Metal Monochalcogenides: Synthesis, Properties, and Applications

“…Post-transition metals typically refer to elements in the periodic table between transition metals and metalloids, with Al, Ga, In, Tl, Ge, Sn, Pb, Sb, and Bi being the most common (some transition metals, such as Zn, Cd, Hg, may also be considered post-transition metals, but are not used here). There are an extensive number of known PTMC compounds with stoichiometries like M 2 III X VI , , M III X VI , ,− M 2 III X 3 VI , − M IV X VI , , M IV X 2 VI , and M 2 V X 3 VI6 (the superscript Roman characters indicate the group to which the element belongs, and the subscript Arabic numerals indicate the stoichiometric number). The MX subgroup (post-transition metal monochalcogenide, i.e., PTMMC) is of particular interest due to their relatively simple crystal structures, and they are the focus of this review.…”