Band Offset Engineering in ZnSnN₂-Based Heterojunction for Low-Cost Solar Cells

A new ternary-alloy, zinc-tin nitride (ZnSnN₂), is considered as one of the most promising absorber materials for photovoltaic applications due to its ideal band gap, rich ternary-chemistry, robust optical absorption, and low cost. In the present work, we demonstrate the ZnSnN₂-based P-N and P-i-N heterojunctions to study the band offset engineering for the development of high-efficiency inorganic solar cell. The P-i-N heterojunction is composed of p-SnO, i-Al₂O₃, and n-ZnSnN₂ constituents. The inclusion of the i-Al₂O₃ buffer layer has remarkably improved the solar cell efficiency by regulating the conduction band offset and interface energy gap. It is believed that our present work will offer a promising approach to manufacture ZnSnN₂-based heterojunctions with better band alignment for novel photovoltaic applications.