Plasmon Induced Conductivity Transition in Monoclinic Gallium Oxide

Conductance transitions offer intriguing possibilities for developing advanced electronic devices. In this study, a reversible conductance transition in β-Ga₂O₃ thin film was realized through plasma treatment and subsequent annealing, where the β-Ga₂O₃ thin films were obtained by MOCVD and CVD methods. This transition is marked by a dramatic increase in carrier density by several orders of magnitude following plasma treating, which then recovers at slightly elevated temperatures. While there is a sharp change in conductivity, the lattice constant and optical bandgap remain nearly constant, with a slight increase in surface roughness and a significant increase in surface potential. A series of electrical tests rule out common donors such as carbon, hydrogen, gallium interstitials, and oxygen vacancies as causes of the increased conductivity observed in this work. Finally, this phenomenon is attributed to changes in the surface atom states. Leveraging this technology, an i-n homojunction photodetector based on β-Ga₂O₃ was fabricated, demonstrating a high on/off ratio and a significant photo/dark current ratio. As β-Ga₂O₃ gains recognition as a fourth-generation semiconductor material, these findings offer promising prospects for advancing the development of innovative electronic devices.