Potential PV materials-based InN thin films: fabrication, structural and optical properties

The fabrication details, as well as basic structural and optical properties, of low temperature plasma enhanced reactively sputtered InN thin films are presented. SEM and AFM studies of surface morphology, including a microstructural cross-section were performed. Optical absorption and reflectance spectra of InN textured films at room temperature in the visible and NIR regions were taken, to reproduce accurately the dielectric function as well as to determine the optical effective mass of electrons (0.11) and the direct band gap (2.03 eV). Some TO (445, 480 and 490 cm−1) and also LO (570 cm−1) phonon features of indium nitride polycrystalline films in the near infrared and Raman spectra are presented and discussed. results, both as obtained now and a few years ago from identical samples just after preparation, are in good agreement. This demonstrates an extraordinary long-term stability of this compound, with respect to its optical and electrical characteristics. The attractive possibilities based on model calculations of InN/Si tandem film systems for potential applications in photovoltaic devices, including high efficiency thin film solar cells, are emphasized and discussed.