Mutual alloying of XAs (X = Ga, In, Al) materials: Tuning the optoelectronic and thermodynamic properties for solar energy applications

摘要

In the present work we did mutual alloying of the versatile XAs (X = Ga, In, Al) materials in order to improve their efficiency and enhance their range of technological applications using state of the art first principles method. We investigate the structural, electronic and thermodynamic properties of Ga_(1-x)Al_xAs, Ga_(1-x)In_xAs and In_(1-x)Al_xAs for x = 0.25, 0.50, and 0.75. Calculations have been performed using the density functional theory (DFT) as implemented within the full potential linearized augmented plane wave plus local orbital (FP-LAPW + lo) method. For exchange and correlation energy treatment, we employed the local density approximations (LDA) as proposed by Wang and Perdew and the generalized gradient approximation (GGA) from Perdew et al. proposed. To calculate the accurate band structure, recently modified Becke Johnson (mBJ) potential was suggested as an alternative. Our calculations show a linear fall in the lattice constant in contrast to linear rise in bulk moduli of Ga_(1-x)Al_xAs and In_(1-x)Al_xAs with the increase of Al concentration. However the change of indium concentration in Ga_(1-x)Al_xAs is displaying a reverse effect. The energy band gap of Ga_(1-x)Al_xAs and In_(1-x)Al_xAs was found to be increased, where a crossover from direct to indirect band gap has been observed with the increase of Al concentration. This direct to indirect crossover was found at 93.4% of Al concentration for Ga_(1-x)Al_xAs and at 84.63% of Al concentration for In_(1-x)Al_xAs. The effect of the mutual alloying of XAs materials on the thermodynamic properties is comprehensively reported.