Optoelectronic characteristics of the Ag-doped Si p-n photodiodes prepared by a facile thermal diffusion process

For the full benefit of the silicon chip industry and to further shift the photoresponse cut-off wavelength of the silicon photodetectors, high-performance Ag-doped Si p-n photodiodes with an extended infrared photoresponsivity are constructed on the bulk silicon wafer by a facile thermal diffusion process at 550 °C for different annealing periods of 5, 10, and 15 minutes under an argon atmosphere. These Si-compatible p-n photodiodes revealed an obvious zero-bias room temperature photoresponsivity with a threshold photon energy at a longer wavelength compared to the photoresponsivity cut-off wavelength of the commercial Si photodiode of the Hamamatsu Photonics Co (model: S2281/-04). The photoresponsivity has decreased with the annealing time increase however; the detectivity has been improved by the significant drop in leakage current and noise power. The outcomes indicate that this study paves the way for developing cost-effective Si-compatible p-n junction photodiodes, with an obvious zero-biased room-temperature photoresponsivity of a comparable intensity and longer cut-off wavelength compared to the commercial Hamamatsu Si photodiode.