Long-wave infrared photodetector structures formed on high-index substrates

Abstract

A layered structure used for detecting incident light includes a substrate having a surface with a high Miller index crystal orientation and a superlattice structure formed over the substrate at the surface. The superlattice structure is aligned to the high Miller index crystal orientation and exhibits a red-shifted long wave infrared response range based on the crystal orientation as compared to a superlattice structure formed over a substrate at a surface with a (100) crystal orientation.

Description

[0001] Cross References to Related Applications [0002] This disclosure claims the benefit of 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 62 / 832,639, filed April 11, 2019, which is hereby incorporated by reference in its entirety. Background technique [0003] Photodetectors typically provide an electronic signal indicative of incident light in some spectral range. For example, some photodetector architectures employ bulk layers to achieve optoelectronic behavior, while others include superlattice structures (SLS). Typically, in the latter type, to increase the operating wavelength of the photodetector, an increased period of the superlattice (SL) is required, since absorption occurs at the interface of the SL where the wavefunctions overlap, so this can lead to an absorbing layer The absorption coefficient per thickness unit or per single SL period of the material decreases. Contents of the invention [0004] The present disclosure is directed to layered...

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Problems solved by technology

Typically, in the latter type, to increase the operating wavelength of the photodetector, an increased period of the superlattice (SL) is required, since absorption occurs at the interface of the SL where the wavefunctions overlap, so this can lead to an absorbing layer Absorption coefficient reduction per thickness unit or per single SL period of the material

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