Strain estimation in III–V materials by analysis of the degree of polarization of luminescence

The degree of polarization (DOP) of luminescence of III–V materials is a sensitive function of the strain in the material. The DOP can be measured with a spatial resolution of roughly 1μm and an rms noise equivalent to a strain difference of 2×10−5. The DOP can be measured on cleaved facets, surfaces free of metals, or luminescent layers buried by transparent materials or thin films. Thus maps of the strain near surfaces for devices and materials can be deduced from analysis of the DOP from the facets or surfaces. Since the reliability and operation of devices depends on strain, DOP measurements have utility in studies of reliability, of enhancement of reliability, and of device operation.