Unstrained III¯V materials have a cubic structure and, owing to symmetry, the probabilities of light being emitted in any two orthogonal polarizations were equal. Mechanical strain, in general, reduced the symmetry of III¯V materials and the probabilities of light being emitted in any two orthogonal polarizations were not necessarily equal. Thus the strain in luminescent III¯V materials could be deduced from measurements of the degree of polarization of luminescence (DOP). Dislocations create characteristic strain fields. The type, direction, and Burgers vector of dislocations near the surfaces of luminescent III¯V materials could be determined by matching measured patterns of DOP with predicted patterns that were based on the characteristic strain fields. In addition, strain fields for defects, quantum wells, interfaces, and steps of fabrication in III¯V materials could be imaged and investigated by analysis of the DOP.

Spatially-Resolved and Polarization-Resolved Photoluminescence for Study of Dislocations and Strain in III-V Materials. D.T.Cassidy: Materials Science and Engineering B, 2002, 91-92, 2-9