Spontaneous polarization field in polar and nonpolar GaInN/GaN quantum well structures

We present a UHV cathodoluminescence study of the spontaneous polarization field in polar [0001] and nonpolar $[1{\bar {1}}00]$ GaN/GaInN single quantum well structures. Employing electron‐stimulated desorption a descreening of the spontaneous field in the polar c‐plane samples was observed, which counteracts the piezoelectric field in the quantum well. While in c‐plane samples a strong blueshift of the emission energy takes place and a drastic increase of emission intensity occurs, no change of the QW emission energy and intensity from m‐plane samples was detected. The different behaviour under the same experimental conditions can only be explained with the absence of the spontaneous polarization field in the nonpolar $[1{\bar {1}}00]$ m‐direction.