Investigation of GaN layers doped with Er3+ and Er3+ + Yb3+ ions using the transmittance measurement

We report about fabrication and properties of Gallium Nitride (GaN) layers doped with erbium or mixture of erbium and ytterbium ions. Transmission spectra in the spectral range from 280 to 800 nm taken by the spectrometer Varian Cary 50 showed that the increasing concentration of the dopants shifts the absorption edge to the lower wavelengths. Optical band gap E g was determined from the absorption coefficient values using Tauc's procedure and the obtained values varied from 3.08 eV to 3.89 eV depending on the erbium or erbium plus ytterbium doping. Photoluminescence emission at 1 530 nm due to the Er 3+ intra-4f 4 I 13/2 → 4 I 15/2 transition was observed by using excitation of semiconductor lasers operating at 980 nm.