The influence of threading dislocation density on electroluminescence and deep level defect incorporation in the multi-quantum well regions of InGaN/GaN light emitting diodes was investigated. The efficiency increased with decreasing threading dislocation density. To elucidate the impact of threading dislocation density on deep level defect incorporation and resulting radiative efficiency, deep level optical spectroscopy and lighted capacitance voltage measurements were applied to the light emitting diodes. Interestingly, the concentration of all observed deep levels decreased with threading dislocation density reduction, but their concentration also varied strongly with depth in the multi-quantum well region. These trends indicated that threading dislocations strongly influenced point defect incorporation into InGaN/GaN light emitting diodes and that threading dislocations, possibly in conjunction with point defects, were detrimental to light-emitting diode efficiency.

Dependence of Radiative Efficiency and Deep Level Defect Incorporation on Threading Dislocation Density for InGaN/GaN Light Emitting Diodes. A.Armstrong, T.A.Henry, D.D.Koleske, M.H.Crawford, K.R.Westlake, S.R.Lee: Applied Physics Letters, 2012, 101[16], 162102