Abstract-Spectroscopic ellipsometry determination of optical and electrical properties of aluminum doped zinc oxide

• Prakash Uprety, 
• Maxwell M. Junda, 
• Kiran Ghimire, 
• Dipendra Adhikari, 
• Corey R. Grice, 
• Nikolas J. Podraza

• Department of Physics and Astronomy & Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA

http://www.sciencedirect.com/science/article/pii/S0169433217301514

An aluminum doped zinc oxide (ZnO:Al) thin film is prepared on soda lime glass by radio frequency (RF) magnetron sputtering. Optical properties of ZnO:Al in the form of complex dielectric function (ε = ε₁ + iε₂) spectra are studied from 0.4 to 6 meV and 0.035 to 5.89 eV using spectroscopic ellipsometry. The film is found to have an optical band gap of 3.62 ± 0.01 eV and an extrapolated DC dielectric constant of 9.072. Resistivity, scattering time, mobility, and carrier concentration are found to be (2.250 ± 0.007) × 10⁻³ Ω-cm, 5.1 ± 0.7 fs, 20.8 cm²V⁻¹s⁻¹, and 1.3 × 10²⁰ cm⁻³ respectively. Resistivity and scattering time resulting from fitting to measurements are found to depend on the spectral range modeled, such that the inclusion of increasingly longer wavelengths results in a convergence to direct electrical property measurements