Optical energy gap of ti:al203 single crystals

The optical absorption spectra of single crystals of titanium doped sapphire (Ti:A1203) with two different doping concentration (0.1% wt. and 0.25% wt.) have been recorded in the UV-visible spectroscopy at room temperature. It was observed that both crystals start to show strong absorptions around 325 run. From this spectrum attempt was made to estimate the values of energy gap and the type of transition occurs in Ti:A1203o From the analysis it show that the optical energy gap are 5.57 eV for 0.1% wt. Ti and 5.94 eV for 0.25 wt.% Ti and it a direct band gap transition