# Demonstration of Si based InAs/GaSb type-II superlattice p-i-n photodetector

## TL;DR

This paper demonstrates a Si-based InAs/GaSb type-II superlattice photodetector for mid-infrared detection, highlighting its performance characteristics and identifying defect-related limitations for future improvements.

## Contribution

It introduces a Si substrate-grown InAs/GaSb superlattice photodetector with detailed characterization, emphasizing defect reduction and surface leakage suppression for enhanced performance.

## Key findings

- Dark current density of 2.3 A/cm2 at 70 K under -0.1 V
- Peak responsivity of 1.2 A/W at ~5.5 μm
- Detectivity of 1.3×10^9 Jones

## Abstract

In this paper, mid-wave infrared photodetection based on an InAs/GaSb type-II superlattice p-i-n photodetector grown directly on Si substrate is demonstrated and characterized. Excitation power dependence on integrated intensity from the photoluminescence measurements reveals a power coefficient of P~I0.74, indicating that defects related process is playing an important role in the predominant recombination channel for photogenerated carriers. At 70 K, the device exhibits a dark current density of 2.3 A/cm2 under -0.1 V bias. Arrhenius analysis of dark current shows activation energies much less than half of the active layer bandgap, which suggests that the device is mainly limited by surface leakage and defect-assisted tunneling, consistent with the photoluminescence analysis. The detector shows 50% cutoff wavelength at ~5.5 um at 70 K under bias of -0.1 V. The corresponding peak responsivity and specific detectivity are 1.2 A/W and 1.3*10e9 cm*Hz1/2/W, respectively. Based on these optoelectronics characterization results, reduction of defects by optimizing the III/V-Si interface, and suppression of surface leakage channels are argued to be the main factors for performance improvement in this Si-based T2SL detector towards low cost, large-format MWIR detection system on Si photonics platform.

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Source: https://tomesphere.com/paper/1906.07351