A discrete core-shell-like micro-light-emitting diode (micro-LED) array was grown on a 100 nm-thick sapphire nano-membrane array without harmful plasma etching for chip singulation. Due to proper design for the sapphire nano-membrane array, an array of multi-faceted micro-LEDs with size of 4 μm × 16 μm was grown. threading dislocation density in the micro-LeD formed on sapphire nano-membrane was reduced by 59.6% due to the sapphire nano-membranes, which serve as compliant substrates, compared to GaN formed on a planar substrate. Enhancements in internal quantum efficiency by 44% and 3.3 times higher photoluminescence intensity were also observed from it. Cathodoluminescence emission at 435 nm was measured from c-plane multiple quantum wells (MQWs), whereas negligible emissions were detected from semi-polar sidewall facets. A core-shell-like MQWs were formed on all facets, hopefully lowering concentration of non-radiative surface recombination centers and reducing leakage current paths. This study provides an attractive platform for micro-LEDs by using sapphire nano-membrane.

The epitaxial growth of an AlN layer on a Si(111) substrate at room temperature by DC magnetron sputtering was investigated. The predeposition of a 5-nm-thick Al layer on the Si substrate before the AlN deposition was found to be crucial for the epitaxial growth of the AlN layer. The orientation relationships of AlN/Al/Si were observed to be AlN½1 100 k Al½0 11 k Si½11 2 and AlN½11 20 k Al[011] k Si½1 10, indicating the epitaxial growth of the AlN layer on the Si(111) substrate. This epitaxial growth of the AlN layer was attributed to the smaller lattice mismatches between AlN½1 100 and Al½0 11 and AlN½11 20 and Al[011] than that between AlN½11 20 and Si½110.

Our results provide in vivo evidence of morphologic changes in the primary somatosensory system, which could be responsible for the sensory functional symptoms of RLS. These results provide a better understanding of the pathophysiology underlying the RLS sensory symptoms and could lead to a potential imaging marker for RLS.