Visible Photoluminescence from InGaPN/GaP Lattice-Matched Single Quantum Well Structures Grown by MOVPE

Optical properties of In_xGa_1-xP_1-yN_y/GaP lattice-matched single quantum wells (SQWs) with different well widths (L_z = 1.6 - 6.4 nm) at different In (x = 0.050 - 0.135) and N (y = 0.025 - 0.071) concentrations have been investigated by low-temperature photoluminescence (PL) and PL-excitation (PLE). The PL spectra showed the strong visible emission from the samples which attracted to a variety of optoelectronic device applications such as light emitting and laser diodes. Comparing to the bulk film, the PL peak position and the fundamental absorption edge of PLE spectra exhibit blue-shift, which correspond to the principally determined by the quantum confinement effect to the well. Comparison between the absorption edge of PLE spectra and the finite square well calculation demonstrate that the effective bandgap energy of InGaPN/GaP system is might be originated from the N-related localized states. With increasing N concentration, the PL peak position exhibits red-shift, which is due to the lowering conduction band edge of InGaPN. On the other hand, the integrated PL intensity is significantly decreased for the SQW with higher In and N concentrations. This probably caused by the larger number of non-radiative process which associated to N-induced trap states.