Substrate temperature dependence of material, optical, and electronic properties of boron-doped ZnO thin films

Abstract Sputtered boron-doped ZnO (BZO) thin films at deposition temperature ranging from 300 °C to 600 °C are studied in this work. The BZO films exhibit preferred orientation of (002) planes. The surface morphology is dependent on deposition temperature, characterized essentially by three distinct features. Hall-effect measurements suggest that the BZO film deposited at 400 °C show the optimum results of carrier concentration, mobility, and resistivity with values that can reach 2.06 × 10 20 cm−3, 5.38 cm2/ V ⋅ s , and 5.64 × 10 − 3 Ω ⋅ cm , respectively. By combining the optical band gap from transmittance spectra and work function from ultraviolet photoemission spectroscopy, the band structure of BZO films is derived. The positions of BZO energy levels presented in this study can provide insights into band engineering in BZO-based optoelectronic devices.