Study of the structural and optical properties of GaPN thin films grown by magnetron RF sputtering

GaP1−xNx thin films were deposited on glass substrates by RF sputtering employing a nitrogen–argon atmosphere in a partial pressure of 2×10−2 Torr. We varied the growth temperature in the range 420–520 °C. The film's optical properties were studied by transmittance and absorbance spectroscopy. Characterization by scanning electron microscopy in cross-sectional view, atomic force microscopy, and X-ray diffraction was performed to determinate the film thickness, surface morphology, and crystal structure, respectively. Raman spectroscopy was employed to analyze the structural properties of samples. The GaP1−xNx films presented a cubic polycrystalline structure with a preferential orientation along the [1 1 1] direction. By varying the growth conditions we were able to change the band gap energy between 1.35 and 1.98 eV.