A UV to NIR Si Wavelength Sensor With Simple Geometry and Good Resolution

In this work, a wavelength sensor that is capable of quantitatively distinguishing the wavelength in the range of ultraviolet (UV) to near-infrared (NIR) light (265–1050 nm) is presented. The wavelength sensor is fabricated by depositing two parallel Au electrodes on the two sides of a $200 ~\mu \text{m}$ 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 technology computer-aided design (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.