Time-resolved photoluminescence from Si-in-SiNx/Si-in-SiC quantum well-dot structures

Si-in-SiNx/Si-in-SiC quantum well-dot structures, with Si quantum dots slightly larger than 1.0 nm embedded in both amorphous SiNx and SiC sublayers, were grown at nearly room temperature by using PECVD. Time-resolved photoluminescence for three samples in a period of 100/30 nm, 60/10 nm and 20/10 nm, respectively, has been measured at emission lengths ranging from 430 nm to 490 nm, and fitted with a stretched-exponential function. Typical decay time was at the order of one nanosecond, which could be attributed to the core-state emission. The matrix materials forming the well provide a non-uniform potential background which induces a modulation to the carrier diffusion process, thus resulting in an emission-wavelength dependent decay time. When confinement effect from the well comes into play as in the sample of smaller well width, the decay time can be below 1.0 ns and indifferent to the varied emission wavelength, and the carrier diffusion is dominated by hopping. These quantum well-dot systems of strong and fast decaying light emission in blue-violet colors might find potential utilization in GHz optical connection and other photoelectronic devices.