Photosensitive Field Emitters with Wide Dynamic Range

Abstract

A new photosensitive field emitter called a “photosensitive floating field emitter” is proposed. It was constructed using an n-type Si field emitter tip and an a-Si : H p-i-n photodiode film. A back incidence type photosensitive floating field emitter was fabricated by depositing intrinsic a-Si : H and p-type a-SiC : H film on the back of a non-gated n-type cone-shaped Si emitter array. The emission current was measured as a function of the illumination intensity and found to increase linearly. The quantum efficiency was about 0.7. However, the emission current tendered to saturate at high illumination level.
To expand the dynamic range of the photodetector, we also examined a photosensitive field emitter composed of a gated field emitter and p-type a-SiC : H/intrinsic a-Si : H photodiode film. Its dynamic range was about 200 times wider than that of non-gated type photosensitive field emitters.