Filterless and High-Speed InP Near-Infrared Photodetector With an Ultra-Small Full-Width at Half Maximum

Abstract

Near-infrared narrowband photodetection between 920 and 960 nm is quite appealing for many applications, such as optical communication, security monitoring, and machine vision, owing to the weak photon-scattering effect and the low intensity of sunlight in this range. Herein, a self-powered narrowband InP photodetector is realized based on a junction-controlled charge-collection narrowing (JCCN) mechanism, exhibiting a peak response centered at 954 nm with a full width at half maximum (FWHM) of 17 nm. Thanks to the reflection of the Schottky electrode and the passivation of the Al2O3 layer, the peak specific detectivity of the device can be up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.5\times 10^{{11}}$ </tex-math></inline-formula> Jones and a linear dynamic range (LDR) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 99 dB is achieved under the illumination of 954 nm. Moreover, the device shows long-term stability and excellent repeatability with a −3 dB frequency of 87.3 kHz. Furthermore, unless the wavelength of the background light is in the range of 945–967 nm, the crosstalk value of the device remains below −10 dB. These results signify that the present InP photodetector is a promising building block for future near-infrared optoelectronic systems.