# Room-temperature high detectivity mid-infrared photodetectors based on black arsenic phosphorus

## TL;DR

This paper introduces black arsenic-phosphorus-based mid-infrared photodetectors operable at room temperature with high detectivity, leveraging van der Waals heterojunctions to enable fast, low-noise detection in the 3-8.2 um range.

## Contribution

The work demonstrates room-temperature MIR photodetectors using black arsenic-phosphorus with high detectivity and zero-bias operation, advancing MIR detection technology.

## Key findings

- Detectivity higher than 4.9×10^9 Jones in 3-5 μm range
- Operates at room temperature up to 8.2 μm
- Zero-bias photovoltaic mode enables fast response

## Abstract

The mid-infrared (MIR) spectral range, pertaining to important applications such as molecular 'fingerprint' imaging, remote sensing, free space telecommunication and optical radar, is of particular scientific interest and technological importance. However, state-of-the-art materials for MIR detection are limited by intrinsic noise and inconvenient fabrication processes, resulting in high cost photodetectors requiring cryogenic operation. We report black arsenic-phosphorus-based long wavelength infrared photodetectors with room temperature operation up to 8.2 um, entering the second MIR atmospheric transmission window. Combined with a van der Waals heterojunction, room temperature specific detectivity higher than 4.9*10^9 Jones was obtained in the 3-5 um range. The photodetector works in a zero-bias photovoltaic mode, enabling fast photoresponse and low dark noise. Our van der Waals heterojunction photodector not only exemplify black arsenic-phosphorus as a promising candidate for MIR opto-electronic applications, but also pave the way for a general strategy to suppress 1/f noise in photonic devices.

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Source: https://tomesphere.com/paper/1705.00801