Oxygen Adsorption and Photoconduction Models for Metal Oxide Semiconductors: A Review

Ultraviolet photodetectors have several critical applications in communications, early missile launch detection, pollution monitoring, and bacterial fluorescence detection. Wide-bandgap metal oxide semiconductors have proven to be high performance ultraviolet photodetectors with some photoresponsivities reaching several orders of magnitude greater than solid state commercial devices and even photo-multiplier tubes. However, analysis and design of metal-oxide photodetectors is complicated by oxygen adsorption and photodesorption at the surface. A limited understanding of this adsorption phenomenon hinders the development of new UV photodetectors. This paper clarifies the adsorption and photodesorption process and makes analysis of metal-oxide photoconductor stractable. Several models of oxygen adsorption, oxygen desorption, and adsorption-controlled conduction from across disciplines are summarized. We discuss each model's use in their intended context, implications for design, fitting parameters, and limitations. We conclude with an argument that current models are insufficient for describing high-gain metal oxide ultraviolet photodetectors, and we outline the requirements for a new model suitable for high-gain sensors.

Automated summary

Ultraviolet photodetectors have critical applications in various fields, with wide-bandgap metal oxide semiconductors being high performance options. However, the complicated analysis and design of these detectors is hindered by oxygen adsorption and photodesorption. Clarifying these processes may lead to the development of new UV photodetectors with higher efficiency.