Self-powered Narrowband Photodetectors Based On N-type Si Schottky-Junction

As an important part of photoelectric system,photodetectors convert radiation energy into electrical signals.In order to improve the immunity of an infrared system,utilizing narrowband photodetector with peak response to target wavelength is an effective method.The specific wavelength window around 1060 nm plays an important role in many fields such as medical imaging,optical communication system,and light detection and ranging,due to the balance of water absorption and scattering effect in this band and the dominant position of 1064 nm in current high repetition rate and power lasers.In this work,a self-powered narrowband photodetector with peak response near 1060nm is realized based on simple Si Schottky junction structure,in which the Ohmic and Schottky electrodes are configured on the front and rear surfaces of Si substrate,respectively.The full width at half maximum of the device decreased from 175 to 107nm as the Si thickness increased from 80 to 500?m.Meanwhile,the peak response slightly red shifted from 1025 to 1050 nm.Experimental results showed that photocurrent of the device went up in an interestingly order which is correlated with the work function value of their Schottky contact material.Device with Au electrodes showed the largest photoresponse with steep rise and fall edges,signifying fast and effective separation of free electron hole pairs by the strong electric field in depletion region.Theoretical simulations also confirmed that the electric field intensity in the depletion region can be effectively enhanced by increasing the work function of schottky contact materials.A specific detection rate of about 1×10¹¹Jones?comparable to the performance of commercial Pb S infrared detectors?and the linear dynamic range of about 101 d B were obtained at zero bias despite the low absorption coefficient at1064 nm.At a low bias of-1 V,its external quantum efficiency can be increased to135%,indicating there is a gain mechanism existed..To the signal of 1064 nm,the Si photodiode represented high noise immunity,showing its promising application in future near infrared optoelectronic devices and systems.