Effects of vacancies and p-doping on the optoelectronic properties of Cu- and Ag-based transparent conducting oxides

First principles band structure calculations are employed to perform a comprehensive study of the electronic and optical properties of the 2H-phase XTO2 (X = Cu, Ag; T = Al, Cr) delafossites, and the effects on those properties due to Cu, Ag, and O vacancies, as well as p-type doping with magnesium. From the band structures, the frequency-dependent real and imaginary parts of the complex dielectric function, ϵ(ω), are obtained, together with refractive index, extinction coefficient, optical conductivity, reflectivity, absorption coefficient, and energy loss function. Moreover, hole effective masses are calculated for all systems and are shown to be highly anisotropic. Comparisons between the results obtained in this work and previous experimental and other theoretical results are made, when available. X vacancies and Mg doping are predicted to only marginally affect the transparent character, but are also predicted to increase the hole effective mass. O vacancies are predicted to lower the hole effective mass, but at the cost of increased absorption in the optical portion of the spectrum, harming transparent character.First principles band structure calculations are employed to perform a comprehensive study of the electronic and optical properties of the 2H-phase XTO2 (X = Cu, Ag; T = Al, Cr) delafossites, and the effects on those properties due to Cu, Ag, and O vacancies, as well as p-type doping with magnesium. From the band structures, the frequency-dependent real and imaginary parts of the complex dielectric function, ϵ(ω), are obtained, together with refractive index, extinction coefficient, optical conductivity, reflectivity, absorption coefficient, and energy loss function. Moreover, hole effective masses are calculated for all systems and are shown to be highly anisotropic. Comparisons between the results obtained in this work and previous experimental and other theoretical results are made, when available. X vacancies and Mg doping are predicted to only marginally affect the transparent character, but are also predicted to increase the hole effective mass. O vacancies are predicted to lower the hole effective...