Structural and Optical Probe into Rare Earth Doped ZnO for Spectral Conversion in Solar Cells

Abstract

This chapter examines the relationship between structure and optoelectronic properties of rare earth doped Zinc oxide (ZnO) thin films fabricated by RF magnetron sputtering for photovoltaic applications. A doped ZnO layer is thus utilized as transparent conducting electrode and as a spectral conversion layer. The high quantum efficiency for emission by ZnO makes it a strong candidate for solid-state white lighting applications as well as transparent conducting electrode in solar cells and electronics. The energy transfer mechanisms from ZnO to the rare earth ions need thorough investigations. The structural and compositional changes in the films at the nanoscale level can influence the luminescence properties. The films were characterized using grazing incidence, Rutherford backscattering spectrometry, atomic force microscopy, UV-visible transmittance and photoluminescence measurements using an excitation wavelength of 244 nm. The optical properties of rare earth doped ZnO usually depend on dopant concentrations, fabrication process and the crystal structure of the host due to the crystal field energy and spin-orbit coupling.