N incorporation and photoluminescence in In-rich InGaAsN grown on InAs by liquid phase epitaxy

Abstract

Dilute nitride InGaAsN layers with high In content have been grown on InAs substrates by liquid phase epitaxy using GaN as a precursor for N in the growth solution. Photoluminescence (PL) was obtained in the mid-infrared spectral range at temperatures between 4 and 300 K. Although Ga increases the InAs bandgap, the strong band anti-crossing effect from the N incorporation resulted in an overall bandgap reduction of 11 meV compared with InAs. The temperature-dependent PL exhibited a complicated behaviour and showed an anomalous increase in intensity from 190 K to room temperature. This was due to the formation in a complex defect which behaves as a non-radiative recombination centre and prevents radiative band–band recombination at temperatures <190 K. Above this temperature the PL increases as band–band transitions become allowed. The formation of this defect requires the presence of both Ga and N and becomes de-activated after a high-temperature anneal. Raman spectroscopy confirmed the presence of phonon modes associated with In–N and Ga–N bonds confirming the incorporation of N using liquid phase growth.