Ge based nano-air-channel photodiode for NIR detector

In this paper, a Ge based nano-air-channel photodiode operated in near infrared band is proposed. It possesses a MOS-like structure composed of Ge substrate, oxide insulation layer/nano-air channel and metal electrode. The nano-air channel is formed between the Ge substrate and the metal electrode by removing the edge of the insulation layer, in which the ballistic transport of the electrons can be realized with. High electric field can be easily achieved on both sides of the nano-air channel at a low voltage, which enables the field emission of the photoelectrons and can be employed for photodetector. The experimental results show that a field emission photocurrent as high as 1.27mA can be abtained under a 850nm laser, which is about 25 times higher than the dark current.