Mid-wavelength focal plane arrays infrared detector based on type-II InAs/GaSb superlattice

A mid-wavelength 128×128\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$128 \times 128$$\end{document} infrared focal plane arrays based on InAs/GaSb type-II superlattice was presented in this work. Superlattice materials were grown on GaSb substrates using MBE technology, which was confirmed by XRD, TEM and AFM analyses. Absorber structure for mid-wavelength detector was designed to be 8 ML InAs/8 ML GaSb. The pixel of the detector had a conventional PIN structure with a size of 50μm×50μm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$50\,\upmu \hbox {m}\times 50\,\upmu \hbox {m}$$\end{document}. The device fabrication process consisted of mesa etching, side-wall passivation, metallization, and flip-chip hybridization with readout integrated circuit, epoxy backfill, lap, and polish. The dark current I–V curve was measured from 77 K up to 297 K. The responsivity spectra, photoluminescence peak wavelength and blackbody current responsivity were measured at 77 K. The detector had a cut-off wavelength of 4.8μm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$4.8\,\upmu \hbox {m}$$\end{document}, photoluminescence peak wavelength of 4.4μm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$4.4\,\upmu \hbox {m}$$\end{document}, peak detectivity of 7.1×1011cmHz1/2W-1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$7.1\times 10^{11}\,\hbox {cm}\,\hbox {Hz}^{1/2}\,\hbox {W}^{-1}$$\end{document}, quantum efficiency of 50 %. The PIN diode may reach a typical value of R0A\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {R}_{0}\hbox {A}$$\end{document} of 5.0×105Ωcm2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$5.0\times 10^{5}\Omega \,\hbox {cm}^{2}$$\end{document}. Pixel operability of the detector was more than 98 %, the non-uniformity was 4.3 %, and the mean NETD value was lower than 20 mK. Concept proof of infrared imaging was also demonstrated with the focal plane array at 77 K.