Nanocrystalline Silicon And Erbium-doped Nanocrystalline Silicon Light-emitting Characteristics

Silicon is the main material of microelectronic device, which has an indirect energy bandage and is therefore highly inefficient as a light source, photoelectronic devices are always expected to be linked with silicon-based microelectronic technology. Although III-V group semi-conductor material, such as GaAs, even is suitable for photoelectronic device, it is much hoped to be fabricated by based- silicon material to carry out silicon- based photoelectronic integration due to present much-mature based- silicon material.This thesis introduced the research history and potential applications of nanocrystalline silicon (nc-Si) and erbium(Er)-doped nc-Si first, then summaried the present research status of them. The luminescence principle of EDFA, nc-Si and Er-doped nc-Si and the shortage of EDFA were all described. The PL properties of nc-Si and Er-doped nc-Si under thermal annealing and deposition oxygen pressure were studied systematically.Silicon suboxides (SiO_x,x<2) thin films on Si matrices were fabricated by pulsed laser deposition (PLD)technique with different deposition oxygen pressure. After deposition, the films were annealed in Ar ambient at different temperature for 30 minutes, as the result nc-Si grew in it. The optic spectrum analyzer was used to analyze the photoluminescence (PL) spectra of the samples at room temperature. It was observed that there was a peak PL intensity at 1000℃, and PL peak wavelength reduced (blueshift) along with the increasing oxygen pressure, which showed the size of nc-Si reducing. At the same time, PL intensity strongly depending on the deposition oxygen pressure was also observed, it reached the peak intensity at the pressure of 20-30mTorr, which was analyzed in the size, cross section and density of nc-Si in detail in the thesis. Er-doped nc-Si was also studied under annealing temperature and deposition oxygen pressure. From the systematical studies of the relations between annealing temperature and integrated PL intensity, it was discovered that the optimal temperature of Er was 900℃. The relation between the integrated PL spectrum of Er and deposition oxygen pressure was similar to that between the integrated PL spectrum of nc-Si and deposition oxygen pressure. They had the same PL spectrum shape, but the optimal oxygen pressure of nc-Si was 20-30mTorr, and that of Er was 40-50mTorr.