Open AccessElectronic structures and optical properties of AAl2C4 (A=Zn, Cd, Hg; C=S, Se) semiconductors
Author(s) -
Chen Dong,
Xiao He-Yang,
Jia Wei,
Hong Chen,
Hang Zhou,
Yi Li,
Kan Ding,
Yongfan Zhang
Publication year - 2012
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.61.127103
Subject(s) - semiconductor , materials science , nonlinear optical , valence (chemistry) , second harmonic generation , band gap , density functional theory , electronic structure , chalcopyrite , molecular physics , optoelectronics , condensed matter physics , optics , nonlinear system , computational chemistry , physics , chemistry , copper , laser , quantum mechanics , metallurgy
First-principles density functional calculations are performed to study the geometries, the electronic and the optical properties of AⅡAl2C4Ⅵ (A =Zn, Cd, Hg; C = S, Se) semiconductors each with a defect chalcopyrite structure. For the linear optical properties, five compounds show good transmissions of light in the IR and part of visible regions, and among them HgAl2S4 and HgAl2Se4 possess moderate birefringences. For the nonlinear optical properties, the strong second harmonic generation (SHG) response can be expected for these crystals, and the large static SHG coefficients ( 20 pm/V) are predicted in this work. The SHG response of AⅡAl2C4Ⅵ semiconductors can be attributed to the transitions from the bands near the top of valence band which are derived from S/Se p states to the unoccupied bands that are contributed by p states of Al and Hg atoms. By comparing with the optical properties of the commercialized AgGaC2 crystals, our results indicate that HgAl2S4 and HgAl2Se4 compounds are good candidates for the second-order nonlinear optical crystals in the IR region.