Photosensitive field emitters including a-Si:H p-i-n photodetection region

A new photosensitive field emitter termed “photosensitive floating field emitter” is proposed. The photosensitive field emitter 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 n-type cone-shaped Si emitter array. The emission current as a function of the illumination intensity was measured and the operation of the photosensitive floating field emitter was described. The possibility of a photosensitive device with more than unit effective quantum efficiency was confirmed using an equivalent circuit for the photosensitive field emitter, which is composed of cone-shaped field emitters (n-type Si) and an avalanche photodiode. It is observed that the emission current exceeds the unit quantum efficiency