Thin-Film Photodetectors for the Ultraviolet and Vacuum Ultraviolet Spectral Range

In this paper we report about thin film photodetectors optimized for the detection of the vacuum ultraviolet. The devi'ces are based on hydrogenated amorphous silicon and silicon carbide p-i -n heterostruclUres on glass substrate. At room temperature the photodetectors exhibit values of quantum efficiency of 52 % at 1..=58.4 nm, I % at 1..=400 nm, and 0.1 % at 1..=650 nm. The time response at ultraviolet pulses from an N2 laser gives signals with 6 Ils full wid£h half maximum and 500 ns rise time. Stability of the device is presently affected by light activation of boron dopant occurs in the p-Iayer under U V illumination and ihas been investigated by a simple equivalent circuit of the structure. The effect can be minimized by optimization on the electrode geometry. The devices are suitable for integration in low-cost, large-area arrays.