On-chip Nanophotonic Broadband Wavelength Detector with 2D-Electron Gas

TL;DR

This paper presents a simple, on-chip broadband wavelength detector using 2D electron gas in ZnO heterojunctions, offering noise resilience, broad spectral range, and easy fabrication for photonics applications.

Contribution

It introduces a novel on-chip wavelength detection method based on photocurrent in ZnO heterojunctions with simple fabrication and noise cancellation capabilities.

Findings

Sensitivity of 0.96 uA/nm over 280 nm wavelength range

Broad spectral detection from 660 to 940 nm

Enhanced noise immunity and heat resistance

Abstract

Miniaturized, low-cost wavelength detectors are gaining enormous interest as we step into the new age of photonics. Incompatibility with integrated circuits or complex fabrication requirement in most of the conventionally used filters necessitates the development of a simple, on-chip platform for easy-to-use wavelength detection system. Also, intensity fluctuations hinder precise, noise free detection of spectral information. Here we propose a novel approach of utilizing wavelength sensitive photocurrent across semiconductor heterojunctions to experimentally validate broadband wavelength detection on an on-chip platform with simple fabrication process. The proposed device utilizes linear frequency response of internal photoemission via 2-D electron gas in a ZnO based heterojunction along with a reference junction for coherent common mode rejection. We report sensitivity of 0.96 uA/nm for a broad wavelength-range of 280 nm from 660-940 nm. Simple fabrication process, efficient intensity noise cancelation along with heat resistance and radiation hardness of ZnO makes the proposed platform simple, low-cost and efficient alternative for several applications such as optical spectrometers, sensing and IOTs.