A "Janus" double sided mid-IR photodetector based on a MIM architecture

TL;DR

This paper introduces a novel mid-IR dual-sided photodetector with a MIM architecture that allows detection from both sides and tunable spectral response, demonstrating promising performance metrics.

Contribution

The work presents the first mid-IR double-sided MIM-based QWIP with tunable spectral coverage and dual-port operation, enabling new detection capabilities.

Findings

Spectral coverage from 7.15 to 8.7 μm achieved by adjusting stripe width.

Similar spectral response from both detector ports confirmed.

Measured T_BLIP of approximately 200K indicating good performance.

Abstract

We present a mid-IR ($\lambda \approx$ 8.3 $\mu$m) quantum well infrared photodetector (QWIP) fabricated on a mid-IR transparent substrate, allowing photodetection with illumination from either the front surface or through the substrate. The device is based on a 400 nm-thick GaAs/AlGaAs semiconductor QWIP heterostructure enclosed in a metal-insulator-metal (MIM) cavity and hosted on a mid-IR transparent ZnSe substrate. Metallic stripes are symmetrically patterned by e-beam lithography on both sides of the active region. The detector spectral coverage spans from $\lambda \approx 7.15$ $\mu$m to $\lambda \approx 8.7$ $\mu$m by changing the stripe width L - from L = 1.0 $\mu$m to L = 1.3 $\mu$m - thus frequency-tuning the optical cavity mode. Both micro-FTIR passive optical characterizations and photocurrent measurements of the two-port system are carried out. They reveal a similar spectral response for the two detector ports, with an experimentally measured T$_{BLIP}$ of $\approx$ 200K.