First Principles Calculation Study of Zn_1-xMg_xO/Cu₂ZnSnS₄Heterointerface

Abstract

Abstract Cu 2 ZnSnS 4 (CZTS) has attracted a lot of attention recently as a promising absorber layer material in a heterojunction solar cell. In this work, the Zn 1-x Mg x O material is substituted for CdS due to its abundant and nontoxic consisting elements. We have studied the band gaps of Zn 1-x Mg x O alloys with different values of x and the band offsets at Zn 0.75 Mg 0.25 O/CZTS heterointerface based on the first-principles and pseudopotential calculation method. The band gaps enhance linearly with the increasing values of x. The total density of state and local density of state of each atom in Zn 0.75 Mg 0.25 O/CZTS supercell are calculated. We predict that the heterojunction of Zn 0.75 Mg 0.25 O/CZTS is a type II heterointerface with a 0.2eV of conduction band offset, during which the conduction band minimum of Zn 0.75 Mg 0.25 O is lower than that of CZTS.