Calculation of electron density of states in rock-salt phase of ZnO by DFT

Publish Year: 1389
نوع سند: مقاله کنفرانسی
زبان: English
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شناسه ملی سند علمی:

MIAUCHEMISTRY01_019

تاریخ نمایه سازی: 18 اسفند 1397

Abstract:

Most of the group II–VI binary compound semiconductors crystallize in either cubic zinc blende or hexagonal wurtzite structure where each anion is surrounded by four cations at the corners of a tetrahedron and vice versa[1]. This tetrahedral coordination is typical of sp3 covalent bonding nature, but these materials also have a substantial ionic character that tends to increase the bandgap beyond the one expected from the covalent bonding. ZnO is a semiconductor whose ionicity resides at the borderline between the covalent and ionic semiconductors[2]. Upon compression above 9.0 GPa, a phase transition to rocksalt-type (B1) structure (space group Fm3m), with an increase in coordination number from 4 to 6 [3]. ZnO is one of the most studied materials in the group of II–VI semiconductors because of its wide band gap 3.44 eV [4] and its bulk exciton-binding energy (60meV)[5], which is larger than the room-temperature thermal energy. In this paper we studied density of states in cubic phase of ZnO semiconductor. Calculation on this structure have been carried out using FP-LAPW method in framework Density functional theory, DFT, and by using WIEN2K pachage [6]. We found that there is hybridization between 2p states in O atoms and 3d states in Zn atoms that it cause band gap estimate. For improve band gap in rock-salt phase of ZnO we used engel-vosko [7] approximation. Also, we calculated electron density of states in (110) and (100) planes that showed ionic future for this phase of ZnO and good agreement was obtained compared to the other results[2].

Authors

H. Salehi

physics Department, Shahid Chamran University, Ahvaz, Iran

S.M. Baizaee

physics Department, Vali-e-Asr University, Rafsanjan, Iran

Azam Soltani Mohammadi

physics Department, Vali-e-Asr University, Rafsanjan, Iran