Opto-electronic and mechanical properties of (CdxZn1−x)2SnO4 in the cubic and orthorhombic phases using first-principles methods

Abstract

We have computationally studied the cubic and orthorhombic (CdxZn1−x)2SnO4 alloy systems (x = 0.00, 0.25, 0.50, 0.75, and 1.00) and investigated their structural, mechanical, vibrational, and opto-electronic properties for photovoltaic applications using density functional theory and beyond methods. The calculated formation energies are below −12.41 eV for the cubic phase and −6.64 eV for the orthorhombic phase. The elastic analysis shows that the bulk moduli for both structures range from 98 to 164 GPa, shear moduli from 41 to 66 GPa, Young’s moduli from 113 to 175 GPa, and the Vickers hardness from 3.18 to 8.95 GPa. All the alloy compositions are mechanically and dynamically stable. The bandgap values, calculated using the hybrid HSE06 functional, range from 1.92 to 2.85 eV and decrease with (Cd). Both structures’ alloys have significantly higher hole effective mass than electron effective mass. A favorable absorption coefficient, along with reflectivity, suggests that the (CdxZn1−x)2SnO4 alloy system can be used as a transparent conducting oxide layer material for solar cell applications.