Electrically Benign Defect Behavior in Zinc Tin Nitride Revealed from First Principles

TL;DR

This study uses first-principles calculations to show that zinc tin nitride lacks deep-level defects, making it a more promising and benign photoabsorber for photovoltaics than previously thought.

Contribution

The paper reveals that ZnSnN2 does not have low-energy deep-level defects, challenging prior reports and improving its prospects as a photovoltaic material.

Findings

ZnSnN2 lacks low-energy deep defects.

Carrier recombination centers are absent in ZnSnN2.

ZnSnN2 is more suitable for photovoltaics than previously believed.

Abstract

Zinc tin nitride (ZnSnN2) is attracting growing interest as a non-toxic and earth-abundant photoabsorber for thin-film photovoltaics. Carrier transport in ZnSnN2 and consequently cell performance are strongly affected by point defects with deep levels acting as carrier recombination centers. In this study, the point defects in ZnSnN2 are revisited by careful first-principles modeling based on recent experimental and theoretical findings. It is shown that ZnSnN2 does not have low-energy defects with deep levels, in contrast to previously reported results. Therefore, ZnSnN2 is more promising as a photoabsorber material than formerly considered.