MOCVD Grown HgCdTe Heterostructures for Medium Wave Infrared Detectors

Waldemar Gawron,Małgorzata Kopytko,Paweł Madejczyk,Jarosław Rutkowski,Tetiana Manyk,Jan Sobieski

doi:10.3390/coatings11050611

Waldemar Gawron, Małgorzata Kopytko + Show 4 more

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https://doi.org/10.3390/coatings11050611

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Abstract

This paper presents the current status of medium-wave infrared (MWIR) detectors at the Military University of Technology’s Institute of Applied Physics and VIGO System S.A. The metal–organic chemical vapor deposition (MOCVD) technique is a very convenient tool for the deposition of HgCdTe epilayers, with a wide range of compositions, used for uncooled infrared detectors. Good compositional and thickness uniformity was achieved on epilayers grown on 2-in-diameter, low-cost (100) GaAs wafers. Most growth was performed on substrates, which were misoriented from (100) by between 2° and 4° in order to minimize growth defects. The large lattice mismatch between GaAs and HgCdTe required the usage of a CdTe buffer layer. The CdTe (111) B buffer layer growth was enforced by suitable nucleation procedure, based on (100) GaAs substrate annealing in a Te-rich atmosphere prior to the buffer deposition. Secondary-ion mass spectrometry (SIMS) showed that ethyl iodide (EI) and tris(dimethylamino)arsenic (TDMAAs) were stable donor and acceptor dopants, respectively. Fully doped (111) HgCdTe heterostructures were grown in order to investigate the devices’ performance in the 3–5 µm infrared band. The uniqueness of the presented technology manifests in a lack of the necessity of time-consuming and troublesome ex situ annealing.

Highlights

Thermal imaging is often used in astronomy and astrophysics to survey distant galaxies, whose near-light speed has shifted their emission spectra from the visible and ultraviolet to the mediumwave infrared (MWIR) region
We present metal– organic chemical vapor deposition (MOCVD)-grown (111) HgCdTe heterostructures for medium-wave infrared detectors operating above 200 K
In this we describe the exemplary results of MWIR photovoltaic detectors

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Many branches of science and industry require detectors operating in the mediumwave infrared (MWIR) band (3–5 μm), where the atmosphere is mostly transparent. This region is typically exploited for thermal imaging, understood as the detection and processing of slight temperature differences in many types of devices and objects, as well as in an environment. Thermal imaging is often used in astronomy and astrophysics to survey distant galaxies, whose near-light speed has shifted their emission spectra from the visible and ultraviolet to the MWIR region

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