Red emission from InGaN active layer grown on nanoscale InGaN pseudosubstrates

Abstract

We demonstrated nanoplatelet InxGa1-xN pseudosubstrates with In content varying from 0 to 0.3 on low-dislocation-density GaN substrates. Since these nanoplatelets efficiently relax in-plane strain, it is possible to use a thick active layer to reduce built-in polarization. The 15-nm-thick InGaN active layers under the same growth conditions on these nanoplatelets shows a remarkable cathodoluminescence redshift from 460 nm to 617 nm, suggesting an enhanced In incorporation efficiency on InGaN nanoplatelets with higher In content. Moreover, the 617 nm emitting sample presented an imperceptible blueshift under excitation-power-dependent photoluminescence, indicating a weak polarization field introduced by the high-In-content pseudosubstrates and the thick active

Cathodoluminescence investigations of dark-line defects in platelet-based InGaN nano-LED structures

“…Using a relaxed platelet with InGaN barriers can result in virtually defect free planar QWs on the flat top-plane of the platelets. A similar approach has been presented in fabricating hexagonal platelets by SAG, but rather than using NWs to seed the platelets, the entire area opened in the mask defines size of the platelets [25,26]. The advantage is that the CMP stage is not needed as the platelets form directly.…”