Design and analysis of a proposed inorganic a-Si/Sb₂S₃ near-infrared narrowband photodetector

Abstract

Abstract There is a significant demand for narrowband photodetectors (NBPDs) operating within the near-infrared (NIR) wavelength range (650 and 900 nm) in various applications, especially in biomedical sensing. In this TCAD computational study, a filter-less NBPD employing a p-n heterojunction a-Si/Sb2Se3 architecture is designed and analyzed. The pivotal aspect of this photodetector lies in its hierarchy, with structure featuring a wider bandgap amorphous silicon (a-Si) material having a thicker layer followed by a slightly narrower bandgap Sb2Se3 material with a shorter film. The detector inorganic architecture FTO/a-Si/Sb2Se3/Au is established within SCAPS-1D numerical simulations, following an experimentally validated NIR NBPD based on CdSe/Sb2(S, Se)3. Simulation results demonstrate that the presented NBPD design exhibits adequate performance with a thickness of 7.0 µm for the a-Si layer and an Sb2Se3-layer thickness of 1.2 µm, achieving a selective spectral response at 684 nm having a full width half-maximum (FWHM) of 35.4 nm and a photoresponsivity of approximately 0.389 A/W under no bias conditions. This a-Si/Sb2Se3 NBPD efficiently detects wavelength range of 650 to 725 nm, offering valuable insights for the development of filter-less low-cost eco-friendly NIR NBPD. Additionally, the proposed structure eliminates the need for an organic hole transportation layer, thereby enhancing the detector stability.