ROLE OF DISLOCATION IN INGAN PHASE-SEPARATION

The role of dislocation for luminescence in InGaN grown on sapphire su bstrate by metal organic chemical vapor deposition (MOCVD) method was investigated by cathodoluminescence (CL) and atomic force microscopy ( AFM). The CL emission area and dark spots between InGaN and GaN layers in InGaN/GaN single quantum well (SQW) and multiple quantum well (MQW ) structures showed completely one to one correspondence. These result s indicate that dislocations in InGaN work as non-radiative recombinat ion centers. Furthermore it was confirmed that the phase separation in InGaN is caused by spiral growth due to mixed dislocations, and such a growth mechanism is discussed.