Optical and Temperature-Dependent Electrical Properties of Ge_1-xPb_xO_y Thin Films for Microbolometer Applications

In this study, an experimental investigation was conducted to explore Ge1-xPbxOy as a candidate material for temperature-sensing layers in uncooled microbolometers. RF and DC sputtering techniques were used to deposit Ge1-xPbxOy thin films with various oxygen concentrations on silicon substrates at room temperature. The composition of the samples was experimentally analyzed using energy dispersive X-ray spectroscopy (EDX) that showed various oxygen concentrations. Atomic force microscopy (AFM) analysis showed excellent average surface roughness ranging from 0.6995 to 0.8660 nm. Increasing the concentration of oxygen up to 31% improved the thermoelectric and optical characteristics of the prepared Ge1-xPbxOy thin films. The highest temperature coefficient of resistance (TCR) of the fabricated samples was -3.85%/K for the Ge0.94Pb0.06O0.31 thin film. By using Essential McLeod software, optical simulation of the thin film samples was performed to assess the highest absorptance of the cavity microbolometer structure, which was 81.88% for the Ge0.94Pb0.06O0.31 thin film.