Time-resolved and temperature-dependent photoluminescence study on phosphorus doped Si quantum dots/SiO 2 multilayers with ultra-small dot sizes

Light emission from Si quantum dots has been extensively studied but the emission wavelength is usually in the visible range, which is not compatible with the requirements of today’s optical telecommunications. Recently, the light emission in the near-infrared range from impurity-doped Si quantum dots were reported but the light emitting mechanism is still an open question. Here we systematically study the phosphorus doping induced sub-band light emission centered at 1250nm in addition to the conventionally observed 890nm emission band in Si quantum dots/SiO2 multilayers with ultra-small dot sizes. It is found that the photoluminescence behaviours of the two independent emission bands are quite different and strongly influenced by the doping concentrations. The time-resolved photoluminescence measurements demonstrate that the 1250nm band has a much shorter lifetime than the 890nm band, which indicates that it has a higher recombination rate to get an efficient emission. Additionally, the temperature dependent photoluminescence measurements are also used to determine the origin of the 1250nm emission.