California Institute of Technology

Arezou Khoshakhlagh

Sarath D Gunapala

David Z Ting

Alexander Soibel

Cory J Hill

Jean Nguyen

Sam A Keo

Disclosed herein is an infrared detector. The detector includes a plurality of pixels. Each pixel includes an n-type semiconductor top contact layer, a p-type semiconductor layer electrically connected to the n-type top contact layer to form a top p-n junction, a unipolar electron barrier electrically connected to the p-type semiconductor layer, a bottom absorber, and an n-type semiconductor bottom contact layer electrically connected to the bottom absorber. The unipolar electron barrier is positioned between the p-type semiconductor layer and the bottom absorber.

Barrier infrared detector architecture for focal plane arrays

Barrier infrared detectors having structures configured to enhance the quantum efficiency, and methods of their manufacture are provided. In particular, device structures for constructing high-performance barrier infrared detectors using novel combinations of p-type and n-type absorber regions and contact regions are provided. The infrared detectors generally incorporate a 'pBpnn' structure. The detectors generally comprise, in sequence, a highly p-doped contact layer 'p', an electron unipolar barrier &#x201c;B&#x201d;, a p-type absorber section &#x201c;p&#x201d;, and n-type absorber section &#x201c;n&#x201d;, and a highly n-doped contact layer &#x201c;n&#x201d;.

Enhanced quantum efficiency barrier infrared detectors

Barrier infrared detectors configured to operate in the long-wave (LW) infrared regime are provided. The barrier infrared detector systems may be configured as pin, pbp, barrier and double heterostructrure infrared detectors incorporating optimized p-doped absorbers capable of taking advantage of high mobility (electron) minority carriers. The absorber may be a p-doped Ga-free InAs/InAsSb material. The p-doping may be accomplished by optimizing the Be doping levels used in the absorber material. The barrier infrared detectors may incorporate individual superlattice layers having narrower periodicity and optimization of Sb composition to achieve cutoff wavelengths of &#x2dc;10 &#x3bc;m.

P-compensated and P-doped superlattice infrared detectors

Dual-band barrier infrared detectors having structures configured to reduce spectral crosstalk between spectral bands and/or enhance quantum efficiency, and methods of their manufacture are provided. In particular, dual-band device structures are provided for constructing high-performance barrier infrared detectors having reduced crosstalk and/or enhance quantum efficiency using novel multi-segmented absorber regions. The novel absorber regions may comprise both p-type and n-type absorber sections. Utilizing such multi-segmented absorbers it is possible to construct any suitable barrier infrared detector having reduced crosstalk, including npBPN, nBPN, pBPN, npBN, npBP, pBN and nBP structures. The pBPN and pBN detector structures have high quantum efficiency and suppresses dark current, but has a smaller etch depth than conventional detectors and does not require a thick bottom contact layer.

Unipolar barrier dual-band infrared detectors

Bias-switchable dual-band infrared detectors and methods of manufacturing such detectors are provided. The infrared detectors are based on a back-to-back heterojunction diode design, where the detector structure consists of, sequentially, a top contact layer, a unipolar hole barrier layer, an absorber layer, a unipolar electron barrier, a second absorber, a second unipolar hole barrier, and a bottom contact layer. In addition, by substantially reducing the width of one of the absorber layers, a single-band infrared detector can also be formed.

Single-band and dual-band infrared detectors

Systems and methods of implementing barrier infrared detectors on lattice mismatched substrates are provided. The barrier infrared detector systems combine an active detector structure (e.g., contact/barrier/absorber pairs) with a non-lattice matched substrate through a multi-layered transitional structure that forms a virtual substrate that can be strain balanced with the detector structure. The transitional metamorphic layer may include one or both of at least one graded metamorphic buffer layer or interfacial misfit array (IMF). A further interfacial layer may be interposed within the transitional structure, in some embodiments this interfacial layer includes at least one layer of AlSb.

Barrier infrared detectors on lattice mismatch substrates

A superlattice-based infrared absorber and the matching electron-blocking and hole-blocking unipolar barriers, absorbers and barriers with graded band gaps, high-performance infrared detectors, and methods of manufacturing such devices are provided herein. The infrared absorber material is made from a superlattice (periodic structure) where each period consists of two or more layers of InAs, InSb, InSbAs, or InGaAs. The layer widths and alloy compositions are chosen to yield the desired energy band gap, absorption strength, and strain balance for the particular application. Furthermore, the periodicity of the superlattice can be 'chirped' (varied) to create a material with a graded or varying energy band gap. The superlattice based barrier infrared detectors described and demonstrated herein have spectral ranges covering the entire 3-5 micron atmospheric transmission window, excellent dark current characteristics operating at least 150K, high yield, and have the potential for high-operability, high-uniformity focal plane arrays.

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Pasadena, CA, United States of America

Arezou Khoshakhlagh