Temperature-dependent photoluminescence of arsenic-doped Si nanocrystals

The characteristics of temperature-dependent photoluminescence (PL) from Si nanocrystals and effects of arsenic-doping (As-doping) were investigated. The Si nanocrystals on a p-type Si substrate were prepared by low pressure chemical vapor deposition and post-deposition thermal oxidation. The As-doping process was carried out using the gas-phase-doping technique. Temperature-dependent PL from Si nanocrystals exhibited considerable differences between samples with/without As-doping. Phase transition between electron–hole liquid and free exciton was observed in the undoped Si nanocrystals, leading to the increase in PL intensity with temperature less than 50 K. Electron emission from As-doped Si nanocrystals to the p-Si substrate was responsible for the significant increase in PL intensity with temperature greater than 50 K. Characteristics of light emission from Si nanocrystals will facilitate the development of silicon-based nanoscaled light-emitting devices.