Tuning of hole carrier density in p-type alpha-SnWO4 by exploiting oxygen defects

The development of p-type oxide semiconductors has shown promise in overcoming limitations restricting the practical usage of oxide semiconductors and the realization of innovative functional devices. Through numerous studies based on both experimental and theoretical approaches, several state-of-the-art p-type oxide semiconductors have been discovered. However, one of the challenges concerning these p-type oxide semiconductors is on tuning the hole carrier density. In this study, precise tuning of the hole carrier density in alpha-SnWO4 based on thermodynamic condition control was demonstrated. A detailed investigation of the crystal structure via X-ray diffraction, extended X-ray absorption fine structures, and density functional theory calculations revealed the role of oxygen defects, such as oxygen vacancies and interstitials, in tuning the hole carrier density. This study shows the importance of fine-tuning of oxygen defects based on thermodynamic condition control for the emergence and improvement of p-type semiconducting properties in Sn2+-based oxides.