Preparation and photoluminescence of nc-Si/SiO2 MQW

摘要

The deposition rate and refractive index for a-Si(amorphous silicon) and SiO$-2$/ grown by PECVD were studied under different pressure, power and proportion of reactant source gases. a-Si/SiO$-2$/ MQW(multi-quantum well) with high quality was deposited under suitable conditions, in which the thickness of the a-Si layers is several nanometers. The sample of a-Si/SiO$-2$/ MQW was crystallized by laser annealing. Because of the confinement of the SiO$-2$/ layers, crystalline grains were formed during the a-Si layers were being crystallized. The size of the crystalline grains were not more than the thickness of the a-Si layers. The a-Si layers were crystallized to be nanometer crystalline silicon (nc-Si), therefore, nc-Si/SiO$-2$/ MQW was formed. For the a-Si/SiO$- 2$/ MQW with 4.0 nm a-Si wells separated by 5 nm SiO$-2$/ barriers, most of the a-Si were crystallized to silicon grains after laser annealing, and the size of the grains is 3.8 nm. Strong photoluminescence with three peaks from the nc-Si/SiO$- 2$/ MQW was detected at 10 K. The wavelength of the peaks were 810 nm, 825 nm and 845 nm, respectively.