Impact Factor:3.98

DOI number:10.1103/PhysRevMaterials.3.125405

Affiliation of Author(s):材料与物理学院

Journal:Physical Review Materials

Funded by:国家自然科学基金

Abstract:Chalcopyrite CuGaSe2 has been widely studied as a promising light-harvesting material for solar cells, but new stable phases and compounds with other stoichiometries of the Cu-Ga-Se ternary systems could have more desirable properties and their optoelectronic properties could be engineered by controlling the degree of disorder. Employing an ab initio evolutionary variable-composition search and Monte Carlo simulations based on the special quasirandom structures, we identified several stable phases of Cu2Se, Ga2Se3, and their alloys CuGaSe2, CuGa3Se5, CuGa5Se8, and Cu(4)Ga(2)Se(5 )at ambient and high pressures. Computed electronic band structures of these alloys indicate that they are semiconductors with direct band gaps ranging from 0.77 eV of Cu4Ga2Se5 to 2.11 eV of CuGa3Se5. Our results disclose anomalous changes in band gap induced by varying chemical composition and applying high pressure, due to the variation in p-d coupling between Se and Cu atoms. Furthermore, the band gap of CuGaSe2 can vary continuously from 1.64 eV for the ordered chalcopyrite structure to 0.23 eV for the fully disordered structure; thus optical absorption spectra in these alloys could be tuned by controlling the synthesis temperature and annealing time, which determine the degree of ordering.

First Author:刘文杰

Co-author:梁汉普

Indexed by:Journal paper

Correspondence Author:段益峰,Zhigang Wu

Discipline:Natural Science

First-Level Discipline:Physics

Volume:3

Issue:12

Page Number:125405

Translation or Not:no

Date of Publication:2019-12-24

Included Journals:SCI

Links to published journals:https://doi.org/10.1103/PhysRevMaterials.3.125405