Improved carrier mobility and bandgap tuning of zinc doped bismuth oxide

The present work attempts to synthesize bismuth oxide and zinc doped bismuth oxide using a citrate gel method to tune the electronic and optical properties suitable for different opto-electronic applications. Techniques like ICP-AES and EDAX were used to determine the compositions of metal in the doped samples. Thermal analyses such as TGA-DTA were used to study the phase change and decomposition temperature of the samples to fix the sintering temperature. Later, the phase purity and crystallinity of sintered and unsintered metal oxides were determined from powder X-ray analysis. The morphology and average particle sizes were obtained from SEM imaging. The doped bismuth oxide shows an increase in bandgap with increase in zinc percentage, which is estimated from DRS measurements. Bulk carrier concentration, sheet concentration, resistivity, conductivity and charge carrier mobility of doped and undoped samples were obtained from hall measurements and the data showed improvement in conductivity and carrier mobility on doping. Increase in carrier mobility and conductivity is attributed to relatively fewer grain barriers due to the smaller size of the doped samples.