Optical properties and electronic subband structures in InxGa1−xN/GaN multiple quantum wells

InxGa1−xN/GaN multiple quantum wells (MQWs) were grown on sapphire substrates by using metalorganic chemical vapor deposition. The optical and electrical properties of the MQWs were investigated photoluminescence (PL) and Hall measurements, respectively. The electronic subband energies, the wave functions, and the Fermi energy in the In0.1Ga0.9N/GaN MQWs were calculated by using a multi-band k→⋅p→ theory and considering the strain due to the lattice mismatch and the spontaneous and piezoelectric polarizations. The potential due to free carriers observed in the Hall measurement was also taken into account in solving the Schrödinger equation and the Pöisson equation self-consistently. The calculated interband transition energy was compared with the PL data. The calculated electronic structure of the In0.1Ga0.9N/GaN MQWs showed that only one subband below the Fermi level was occupied by the electrons.