Mid-IR InAsSb photovoltaic detectors

Abstract

We describe a mid-JR photovoltaic detector using InAsSb as active material, grown by MBE on a GaSb substrate. The purpose of this study is to show that quantum detectors can offer an alternative to thermal detectors (pyroelectric or resistive holometers) for high temperature (near room temperature) operation. With a 9% Sb content, InAsSb is lattice matched to GaSh and thus provides an excellent material quality, with Shokley-Read lifetimes of the order of 200 ns as measured by photoconductive gain measurements as well as time resolved photoconductivity experiments. The band gap of InAsSb corresponds to a wavelength of 5 microns at room temperature. This makes InAsSb an ideal candidate for room temperature detection in the 3-5 microns atmospheric window. Photovoltaic structures are characterized by current voltage characteristics as a function of temperature. Using the absorption value obtained on the test samples, a detectivity of 7X109 Jones can he obtained at a temperature of 250 K, which can easily be reached with Peltier cooling. This leads to a NETD lower than 80 mK.

Photonic structure enhancement on photodetection

“…The mesh size was set to 5 nm in all simulations. The dielectric constant of the heterostructure photodiode was obtained from previously reported data [142]. The detector was illuminated with the plane waves and the absorption spectra were calculated by subtracting transmission and reflection, where the power monitors for reflection and transmission are positioned above the detector structure and below the substrate, respectively.…”

“…Periodic boundary conditions were used in the SRR unit cell and the mesh size was set to 1 nm in all simulations. The permittivity of gold was obtained from Palik [141], while the dielectric constant of the heterostructure photodiode was obtained from measured data and published literatures [142]. The dimensions of all the simulated SRRs on both heterojunction and silicon samples are presented in Table V.…”

“…Plasmonic Structures for Enhancement of MIR Photodetection InAsSb absorber, numerical FDTD was used to calculate the reflection spectra and distribution of optical field of the rotated fourfold U-shape SRR array. In simulation, the permittivity of gold was extracted from the book by Palik [141] and that of the heterojunction photodiode from measured data and published literatures [142], [153]. Following conventional rules [140], [154],…”