Carrier Tuning in ZnSnN2 by Forming Amorphous and Microcrystalline Phases

• Published in: Inorganic chemistry Vol. 58; no. 13; pp. 8480 - 8485
• Main Authors: Wu, Xiaojie, Meng, Fanzhi, Chu, Deliang, Yao, Mingcai, Guan, Kai, Zhang, Dongdong, Meng, Jian
• Format: Journal Article
• Language: English
• Published: American Chemical Society 01.07.2019
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.9b00649

ZnSnN2 (ZTN), an earth-abundant element semiconductor, is a potential candidate for photovoltaic applications. However, the excessively high n-type carrier concentration caused by intrinsic defects hinders its progress. In this work, a series of Zn1±x SnN2 thin films are fabricated by RF-magnetron sputtering deposition. The zinc-rich composition is found to promote the crystallization of ZTN. As a main source of n-type carriers in the zinc-rich thin films, the interstitial Zn dominates the change of carrier concentration with an increase in the Zn/Sn ratio. Near the stoichiometric ratio, amorphous ZTN (a-ZTN) thin films are fabricated, and the n-type carrier concentration is suppressed to 1016 cm–3. With an increase in the Zn/Sn ratio from 0.9 to 1.3, the n-type carrier concentration can be tuned in the range 1016–1019 cm–3, accompanied by the phase-transition from a-ZTN to microcrystalline ZTN (μc-ZTN). For the a-ZTN thin film, the carrier mobility reaches up to 7 cm2 V–1 s–1, and the photoresponse covers almost the whole visible band. The above properties demonstrate that a-ZTN and μc-ZTN are potential candidates for photovoltaic applications.