Investigation of deep levels in porous silicon by photoconductivity decay and thermally stimulated depolarization current methods

摘要

The photoconductivity measurements of porous silicon were made using the visible light in wavelength range of 450 nm-1200 nm. Obtained photoconductivity spectra were decomposed as a sum of Gaussian. The deep level energies are calculated for these peaks at about 1.24 eV, 1.33 eV, 1.55 eV, 1.84 eV, 2.17 eV and 2.54 eV at room temperature. To characterizing the deep levels we used also thermally stimulated depolarizaton current method (TSDC). In this case we used a thermal stimulation in temperature range of about 90 K-300 K in vaccuum. After multigaussian decomposing of the current-temperature characteristic we calculated the thermal deep levels energies (0.4 eV and 0.8 eV). From the voltage-current measurements ideality factor was also calculated.