Near-field photoluminescence imaging of single defects in a ZnSe quantum-well structure at low temperatures

Single bright-spot, bow-tie-shaped defects in a ZnSe heterostructure are spectroscopically imaged with 200 nm spatial resolution at a sample temperature of 20 K. The local thickness variations in the single ZnSe quantum-well lead to a lateral double-well potential resulting in a shift and enhancement of the quantum-well photoluminescence. The luminescence images of the ZnMgSSe barrier material are governed by nonradiative recombination at the four associated Frank partial dislocations.