Indium incorporation in GaInN quantum wells on various surface orientations

While GaN based blue-violet lasers are commercially available, several problems occur on the way towards the green spectral region. Among others the high indium contents needed for green emission result in high piezoelectric fields which dramatically reduce the oscillator strength. One promising approach to reduce the influence of polarization fields is to grow on non- or semipolar surfaces of the wurtzite structure. In this contribution we compare the In incorporation in GaInN multiple quantum wells on various surface orientations. Our samples were grown by MOVPE on bulk GaN substrates, (HVPE) GaN templates or foreign substrates. The In content in the QWs was determined by high resolution X-ray diffraction and photoluminescence. Applying the same growth conditions we find similar growth rates and In contents for the nonpolar layers compared to conventional c-plane structures. Preliminary experiments indicate that the In incorporation on the semipolar (11 anti 22)-plane is significantly larger which is assigned to a reduction of the strain-induced repulsive interaction between incorporated In atoms on the surface.