Strain and temperature distribution in broad-area high-power laser diodes under operation determined by high resolution X-ray diffraction and topography

Broad-area lasers were investigated by high resolution X-ray diffraction (H RXRD) and topography, before and during laser operation. Rocking curves wer e taken at different positions of the 150 mum wide and 2 mm long laser stri pe? using high-precision motorized slits with a spatial resolution of 40 x 40 mum(2). From the series of rocking curves recorded at different lateral positions and driving currents, the curvature and temperature profiles alon g the stripe could be estimated for different driving currents. X-ray topog raphs revealed regions with higher strain compared to the surrounding area. At lateral positions within the stripe, where the highest temperature was determined by HRXRD, regions of dark contrasts, indicating defects, were de tected by cathodoluminesceace. Transmission electron microscopy revealed th at the highly strained regions act as sinks for point defects, since no dis locations or dislocation loops were detected. Thus, a clear con elation bet ween temperature rise, high local strain and defect formation was found. (C ) 2001 Elsevier Science B.V. All rights reserved.