Strong Photovoltaic Effect In High-Density Inalas And Inas/Inalas Quantum-Dot Infrared Photodetectors

We report on a high responsivity at zero bias in infrared photodetectors based on InAlAs quantum dots due to the formation of an Al-rich wetting layer which acts as an electron barrier. This layer has a larger bandgap and results from the low segregation and low surface diffusion of the Al atoms that mostly remain inside the wetting layer. These photovoltaic infrared photodetectors could operate up to 80 K and presented a detectivity similar to the one of a conventional photoconductive photodetector based on InAs quantum dots, despite the lack of optimization for photovoltaic operation. Such InAlAs devices might be good candidates for focal plane arrays that require low dark current, low noise, and low current consumption. (c) 2020 Elsevier B.V. All rights reserved.