Photoluminescence Of Nanocrystalline SiC Films And Its Surface Plasmon Enhancement

Nanocrystalline silicon carbide (SiC) thin films have been deposited by helicon wave plasma enhanced chemical vapor deposition (HWP-CVD) on single crystalline silicon and quartz substrates. A variety of techniques, including atomic force microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible transmittance and reflection spectroscopy, and photoluminescence (PL) spectra are utilized to investigate and analyze the properties of component, microstructure, optical band gap and PL of the prepared films. The effects of substrate temperature on the structural and especially optical properties of the deposited films are studied. The microstructure analyses of the deposited films indicate that the deposited films are in a typical structure of SiC nanocrystals embedded in the matrix of its amorphous counterpart. With increasing the substrate temperature, the size of SiC nanocrystals decreases, the surface roughness and crystalinity of the deposited films increase. The analyses of optical absorption and photoluminescence properties show that with increasing the substrate temperature, the optical band gap and order degree of the deposited films increase, and the blueshifts of their PL peaks occur which indicates that the PL is relate to the quantum confinement effect of SiC nanocrystals.According to the theory of surface plasmon resonance of metal nanoparticals, nano-silver films with different thickness are deposited by magnetron sputtering technique on Corning glass substrates. It is found that with the increase of the nano-silver films thickness, the size of Ag nanoparticles increases, the surface plasmon resonance wavelength has red-shift, and the adjustments of surface plasmon resonance wavelength in the range of visible-near infrared light are achieved.The typical SiC/a-SiNx/Ag multilayer films are fabricated by HWP-CVD and magnetron sputtering techniques. The properties of surface plasmon enhancement of PL are analyzed. It is found that surface plasmon excitation exits the absorption enhancement, Purcel enhancement and cavity mode interference enhancement, and the obviously surface plasmon enhancement of PL only can be observed in their interference area.