Open AccessFirst principles study of Bismuth alloying effects in GaAs saturable absorber
Author(s) -
Dechun Li,
Ming Yang,
Shengzhi Zhao,
Yongqing Cai,
Yuanping Feng
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.011574
Subject(s) - materials science , saturable absorption , bismuth , band gap , doping , semiconductor , absorption edge , absorption (acoustics) , optoelectronics , impurity , laser , optics , condensed matter physics , fiber laser , chemistry , physics , wavelength , metallurgy , composite material , organic chemistry
First principles hybrid functional calculations have been carried out to study electronic properties of GaAs with Bi alloying effects. It is found that the doping of Bi into GaAs reduces the bandgap due to the intraband level repulsions between Bi induced states and host states, and the Bi-related impurity states originate from the hybridization of Bi-6p and its nearest As-4p orbitals. With the increase of Bi concentration in GaAs, the bandgap decreases monotonously. The calculated optical properties of the undoped and Bi-doped GaAs are similar except the shift toward lower energy of absorption edge and main absorption peaks with Bi doping. These results suggest a promising application of GaBi(x)As(1-x) alloy as semiconductor saturable absorber in Q-switched or mode-locked laser.