Nitrogen doped Cu2O: A possible material for intermediate band solar cells?

The optical properties of sputtered Cu2O thin films doped with the nitrogen concentrations between 1 and 2.5 at% have been investigated by spectrophotometric measurements. All the doped samples exhibit two clearly defined absorption bands at energies below the gap, with an intensity well correlated with the N concentration. This result suggests Cu2O as a promising material for the development of intermediate band solar cells, also considering the band gap of about 2 eV which is the optimal value for this kind of devices. Moreover, the sample with the highest doping shows a resistivity of 1.14 Ω cm , which is the lowest value ever reported for this semiconductor. As a collateral result, we provide a first estimation of the Relative Sensitivity Factors (RSF) of nitrogen and oxygen atoms under Cs + bombardment in a Cu2O matrix.