Can Fu, Chuan Lu, Hai-Yang Cheng, Xiang Zhang, Zhi-Xiang Zhang, Yu-Tian Xiao, Di-Hua Lin, Jiang Wang, Ji-Gang Hu,  Zhi-Li Wang, Di Wu, Lin-Bao Luo*

Abstract: In this work, a wavelength sensor that is capable of quantitatively distinguishing the wavelength in the range of ultraviolet to near-infrared light (265 to 1050 nm) is presented. The wavelength sensor is fabricated by depositing two parallel Au electrodes on the two sides of a 200 μm Si wafer. It is found that the as-formed two photodetectors display completely different optical properties. And then, the relationship between the photocurrent ratio of two photodetectors and incident wavelength can be described as a numerical function, through which the wavelength from 265 to 1050 nm can be precisely calculated. The unique operation mechanism of the Si wavelength sensor is unveiled by TCAD simulation. Remarkably, the wavelength sensor easily distinguishes the light with a wavelength difference of 1 nm, which is much better than previously reported devices based on the vertically stacked structures and charge collection narrowing mechanism.