First-Principles Study of Point Defects in GaAs/AlAs Superlattice: the Phase Stability and the Effects on the Band Structure and Carrier Mobility

Table 5 The band gap, electron effective mass at the Γ point (\( {m}_{\Gamma}^{\ast } \)), and electron mobility along the z direction, i.e., Γ-X direction in the Brillouin zone (μ_Γ − X) for defective GaAs/AlAs superlattice

Defect type	Band gap (eV)	Effective mass (\( {m}_{\Gamma}^{\ast } \))	Electron mobility (μ_Γ − X)
Ideal
–	2.06	0.113 (0.07^a)	0.623 (1.0^a)
Antisite
Ga_Al	1.98	0.124	0.567
Al_Ga	2.01	0.142	0.496
As_Ga	–	0.163	0.432
As_Al	–	0.119	0.591
Ga_As	0.1	0.267	0.263
Al_As	0.15	0.227	0.311
Interstitial
Ga_int	–	0.313	0.225
Al_int	–	0.289	0.243
As_int	–	0.223	0.315
Vacancy
V_Ga	0.47	0.729	0.097
V_Al	0.44	0.682	0.103

X_Y: (X, Y = Ga, Al, or As) X occupying the Y lattice site; V_X: X vacancy; X_int: X interstitial. \( {m}_{\Gamma}^{\ast } \) in the units of the static electron mass m_e; μ_Γ − X in the units of 10⁴ cm²/Vs. ^aRef. [38]