Through the studying of the carriers moving of the porous and the definition of S BET ,the equation of the relationship among the porosity,the current density and the etching speed can be deduced.Here,it is sh...Through the studying of the carriers moving of the porous and the definition of S BET ,the equation of the relationship among the porosity,the current density and the etching speed can be deduced.Here,it is shown that for porous silicon made from p type silicon,there is a universal relationship,it is possible to determine the change in porosity with respect to etching under a set etching current density.This relationship is checked against experimental data from several reports on these etching parameters,and they confirm the validity.展开更多
Porous silicon(PS) was found to emit visible luminescence at room temperature. This phenomenon implies a potential application of silicon in optoelectronics. The luminescence of PS can be improved by doping with rare ...Porous silicon(PS) was found to emit visible luminescence at room temperature. This phenomenon implies a potential application of silicon in optoelectronics. The luminescence of PS can be improved by doping with rare earth elements. A new electrochemical doping approach, constant potential electrolysis, and a new electrolyte system for doping of porous silicon with holmium were reported. By this approach and system, the doping products were well controlled, and Ho doped PS(HDPS) was found to emit much intenser visible photoluminescence with blue shift in wavelength and higher luminescence stability at room temperature than that for corresponding PS wafer. The effects of various kinds of holmium compounds, solvents, applied voltage, concentration of holmium nitrate and doping time on photoluminescence of HDPS were investigated, and the optimum doping conditions were fixed. The luminescence mechanisms for PS and HDPS were discussed.展开更多
文摘Through the studying of the carriers moving of the porous and the definition of S BET ,the equation of the relationship among the porosity,the current density and the etching speed can be deduced.Here,it is shown that for porous silicon made from p type silicon,there is a universal relationship,it is possible to determine the change in porosity with respect to etching under a set etching current density.This relationship is checked against experimental data from several reports on these etching parameters,and they confirm the validity.
文摘Porous silicon(PS) was found to emit visible luminescence at room temperature. This phenomenon implies a potential application of silicon in optoelectronics. The luminescence of PS can be improved by doping with rare earth elements. A new electrochemical doping approach, constant potential electrolysis, and a new electrolyte system for doping of porous silicon with holmium were reported. By this approach and system, the doping products were well controlled, and Ho doped PS(HDPS) was found to emit much intenser visible photoluminescence with blue shift in wavelength and higher luminescence stability at room temperature than that for corresponding PS wafer. The effects of various kinds of holmium compounds, solvents, applied voltage, concentration of holmium nitrate and doping time on photoluminescence of HDPS were investigated, and the optimum doping conditions were fixed. The luminescence mechanisms for PS and HDPS were discussed.
