Structural and optical properties of InGaN/GaN multiple quantum wells: Theeffect of the number of InGaN/GaN pairs

The effect of the number of InGaN/GaN quantum well (QW) pairs on the interf acial structural and optical properties of InGaN/GaN multiple quantum wells (MQWs), as grown by low-pressure metalorganic vapor-phase epitaxy was exam ined. As the number of QW pairs increased, In-rich InGaN precipitates were more readily detected in the InCaN/GaN MQWs by cross-sectional transmission electron microscope. The intensity of the photoluminescence (PL) peak was decreased and the PL peak was red-shifted with an increase in the number of QW pairs. X-ray diffraction measurements revealed that the interfacial str ucture between InGaN and GaN were also deteriorated with the increasing num ber of QW pairs. These results can be attributed to the relaxation of an ac cumulated strain through the dislocations induced by an increase in the tot al thickness of the MQWs with an increase in the number of QW pairs. These results suggest that the defects such as dislocations facilitate the format ion of In-rich phases in the InGaN layers in the MQWs. (C) 2000 Elsevier Sc ience B.V. All rights reserved.