Influence of Nitrogen Content on Persistent Photoconductivity in Zinc Oxynitride Thin Film Transistors

In this work, the influence of anion composition on the photoresponse characteristics of zinc oxynitride thin film transistors is investigated and compared directly to conventional In-Ga-Zn-O TFTs. Increasing the ratio of N to (N+O) led to higher field effect mobility and improved subthreshold swing. The subgap density of states extracted by monochromatic photonic capacitance-voltage measurement indicated that the nitrogen-related defect states, such as nitrogen vacancies, increased with increasing nitrogen gas flow rate. Furthermore, the photoconductivity mechanism of ZnON TFTs is discussed in detail.