Barium oxide-based photodetectors engineered for visible light and near-infrared communication applications

Thermally deposited p-type barium oxide (BaO) thin films, coated with a 50-nm-thick silicon oxide (p-SiO2) protective layer, are employed as photodetectors. In a vacuum environment with a pressure of 10(-)5 mbar, stacked layers of p-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p-$$\end{document} BaO and p-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p-$$\end{document} SiO2 are grown onto n-type Si substrates. Structural investigations revealed the preferred growth of the tetragonal phase of BaO. Temperature-dependent electrical resistivity and optical absorption measurements determined a work function of 4.29 eV for p-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p-$$\end{document} BaO. Additionally, the design of the energy band diagram indicated an almost negligible built-in potential at the -Si/p-BaO interface. The resulting n-Si/p-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p-$$\end{document} BaO/p-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p-$$\end{document} SiO2 photodetectors demonstrated high current responsivities of 0.24 A/W, 0.17 A/W, and 4.5 A/W under illumination with blue, red, and near-infrared (NIR) light, respectively. Corresponding external quantum efficiency percentages exceeded 69%, 34%, and 580%. Furthermore, the calculated photodetector parameters, including specific detectivity, noise equivalent power, linear dynamic range, and time-dependent current growth/decay cycles, confirmed the suitability of the proposed devices for visible light and NIR communication technologies.