Electrochemical modulation of Te material morphology and performance of Si/Te photodetectors

Abstract

Silicon (Si) material has a lower cost and mature preparation process, epitaxial growth of tellurium (Te) material with narrow bandgap on Si substrate and preparation of Si-based detector can not only broaden the response band of silicon material but also improve the device response speed. In this paper, electrochemical deposition was used to grow Te materials inside a patterned silicon window to prepare Si/Te photodetectors. By regulating the pH of precursor solution and deposition time, the chemical reaction of Te during deposition and the crystal structure under relative conditions were investigated, as well as growing nanowire-type, feather-type, nanosheet-type, and nanorod-type Te materials. Finally, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction methods characterized the Te with different morphologies. Our results illustrate that the higher the pH of the Te material, the slower the reduction reaction rate, and the alkaline condition requires a larger deposition voltage. After photovoltaic testing, all three conditions responded to lasers at 635 nm and 1550 nm wavelengths, which lays the foundation for dual-band Si/Te photodetectors.