MoO3 lamellar single crystals were processed into planar metal-semiconductor-metal devices and subjected to irradiation cycles with ultraviolet light and 2 MeV protons in vacuum. In-situ electrical characterization demonstrates that these sensor devices respond well to the radiation with a gain of ~30% upon proton irradiation. However, response times are slow and strong persistent photoconductivity and ion beam induced conductivity are observed when the excitation source is switched off. The current decay is strongly increased when the irradiation chamber is vented with air suggesting that surface processes are at the origin of persistent conductivity. The observed conductivity changes are explained based on a model considering the creation of electron-hole pairs as well as adsorption and desorption processes of oxygen molecules at the surface of the samples.
- Ion beam induced conductivity
- Molybdenum trioxide