Electronic properties of Fe impurities in SnS van der Waals crystals - Revealing high-mobility holes

Defect control is critical to achieve long carrier lifetimes in semiconductors. SnS is a promising thermoelectric and photovoltaic material, in which native defects play a detrimental role, particularly in photovoltaics. In this study, we investigated the Fe-doping of SnS and the interaction of Fe impurities with native defects in a series of single crystals of Sn1-xFexS up to concentrations of x = 0.05. Although the doped single crystals appear rather disordered, the hole mobility is very high (similar to 8500 cm(2)V(-1)s(-1) at 30 K for Sn0.99Fe0.01S), suggesting that holemediated charge transport in this material is largely insensitive to extrinsic impurities. Charge transport analysis suggests that the incorporation of Fe atoms leads to the healing of the intrinsic defect structure and the exclusion of minority electrons from charge transport, allowing the observation of high hole mobility.