Influence of Bi concentration on structural and optical properties of Bi doped p-type ZnO thin films prepared by sol–gel method

This paper reports the growth of stable p-type ZnO film on p-Si substrate. The bismuth doped ZnO (Bi doped ZnO) thin films have been grown by sol–gel spin coating method followed by thermal annealing. The structural studies performed exhibits that Bi doped ZnO thin film possess highly crystalline nature with c-axis orientation. The electrical conductivity of the deposited film has been determined by Seeback voltage measurement and its stability has been studied as function of time. Interestingly it was observed that ZnO thin films retain p-type nature even after 150 days. Further, optical band gap and reflectance of Bi doped ZnO films have also been determined with varying concentrations of Bi using the data taken by ellipsometer.