Visible-blind ultra-violet detector based on n-ZnO/p-Si heterojunction fabricated by plasma-assisted pulsed laser deposition

The n-Zn/p-Si heterostructure detector for ultra-violet was fabricated by pulsed laser deposition. Plasma oxygen was used for the deposition of n-ZnO thin films to decrease the concentration of deep-level defects such as oxygen vacancies and zinc interstitials. The electron concentration of n-ZnO thin film was reduced to a low level of 10¹⁴ cm^-3, resulting in the depletion width in p-Si decreasing significantly. The spectral response of the detector shows that the responsivity to visible light has been eliminated effectively by using plasma oxygen in the ZnO film growth. The visible-blind mechanism for the n-Zn/p-Si heterostructure detector has been discussed.