Prediction and realisation of high mobility and degenerate p-type conductivity in CaCuP thin films
Joe Willis, Ivona Bravić, Rekha R. Schnepf, Karen N. Heinselman, Bartomeu Monserrat, Thomas Unold, Andriy Zakutayev, David O. Scanlon, Andrea Crovetto
Abstract
at room temperature, respectively. Transport calculations indicate potential for even higher mobilities. Copper vacancies are identified as the main source of conductivity, displaying markedly different behaviour compared to typical p-type transparent conductors, leading to improved electronic properties. The optical transparency of CaCuP films is lower than expected from first principles calculations of phonon-mediated indirect transitions. This discrepancy could be partly attributed to crystalline imperfections within the films, increasing the strength of indirect transitions. We determine the transparent conductor figure of merit of CaCuP films as a function of composition, revealing links between stoichiometry, crystalline quality, and opto-electronic properties. These findings provide a promising initial assessment of the viability of CaCuP as a p-type transparent contact.