Room-Temperature Midwavelength Infrared InAsSb Nanowire Photodetector Arrays with Al₂O₃ Passivation

Abstract

Developing uncooled photodetectors at mid-wavelength infrared (MWIR) is critical for various applications including remote sensing, heat seeking, spectroscopy, and more. In this study, we demonstrate room-temperature operation of nanowire-based photodetectors at MWIR composed of vertical selectivearea InAsSb nanowire photoabsorber arrays on large bandgap InP substrate with nanoscale plasmonic gratings. We accomplish this by significantly suppressing the nonradiative recombination at the InAsSb nanowire surfaces by introducing ex-situ conformal Al2O3 passivation shells. Transient simulations estimate an extremely low surface recombination velocity on the order of 10 3 cm/s. We further achieve room-temperature photoluminescence emission from InAsSb nanowires, spanning the entire MWIR regime from 3 µm to 5 µm. A dry-etching process is developed to expose only the top nanowire facets for metal contacts, with the sidewalls conformally covered by Al2O3 shells, allowing for a higher internal quantum efficiency. Based on these techniques, we fabricate nanowire photodetectors with an optimized pitch and diameter and demonstrate room-temperature spectral response with MWIR detection signatures up to 3.4 µm. The results of this work indicate that uncooled focal plane arrays at MWIR on low-cost InP substrates can be designed with nanostructured absorbers for highly compact and fully integrated detection platforms.

An Integrated Flexible All‐Nanowire Infrared Sensing System with Record Photosensitivity

“…[ 5–10 ] With this in mind, various low‐dimensional nanostructures, especially nanowires (NWs) and two‐dimensional (2D) materials, have been extensively investigated in the past few years. [ 11–16 ] For example, Hu and co‐workers fabricated IR detectors based on parallel GaSb NW arrays that exhibited a photosensitivity of 4.5 with rise and decay times of 195.1 and 380.4 µs, respectively. [ 13 ] Many of IR detectors have been recently built on various 2D semiconducting nanostructures with varying photosensitivities, response speeds, etc.…”

Circular Polarization Discrimination Enhanced by Anisotropic Media

“…Vertical semiconductor nanowire arrays have been widely investigated for photodetectors, [ 37–41 ] solar cells, [ 42 ] LEDs, [ 43 ] lasers, [ 44 ] and sensors [ 45 ] owing to their unique properties, such as their anisotropic geometry, high surface‐to‐volume ratio, small footprint, crystalline perfection, and light trapping effect. [ 46,47 ] In the following, we present that the integration of a nanowire array with an asymmetric metamaterial leads to a high CPER due to the optical anisotropy of the nanowires.…”

Surface/Interface Engineering for Constructing Advanced Nanostructured Photodetectors with Improved Performance: A Brief Review

“…The surface states of ZnO nanowalls was suppressed due to the introduction of CdS nanoparticles' passivation layer; thus, the deep-level emission was reduced, and the recombination of carriers was prevented, and then the photoconductivity of ZnO nanowalls was improved obviously. Ren et al [38] constructed nanowire-based photodetectors at mid-wavelength infrared composed of vertical selective-area n-InAsSb nanowire photoabsorber arrays on large bandgap p-InP substrate. In order to effectively inhibit the nonradiative recombination at the surface of InAsSb nanowire, the Al 2 O 3 passivation shells were introduced, as displayed in Figure 2a,b.…”

“…From the conclusion of the literature review, it could be illustrated that compared with film and bulk materials, low-dimensional nanostructures have the advantages of unique conductivity caused by high quality of crystal and carrier mobility and a confined carrier transport channel; thus, they are much more suitable candidate materials in assembling high-performance PDs on a large scale [34]. It could also be found that at this stage, various nanostructures of different materials have been utilized to fabricate PDs, including quantum dots (QDs) [24], nanoparticles (NPs) [35,36], nanowires [37][38][39], nanotubes [40], nanosheets [41,42], nanoribbons [43], nanobelts [44], and so on.…”