UPSI Digital Repository (UDRep)
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UPSI Digital Repository (UDRep)
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| Abstract : Universiti Pendidikan Sultan Idris |
| To date, considerable research has been devoted to semipolar (11-22) III-N based-light-emitting diodes due to the high demand for the future generation of high indium adsorption materials. However, higher indium content can generate stacking fault defects and partial dislocation that deteriorate the crystal, morphological, and optical quality. This study describes the effect of indium flux and two-dimensional nanoscale strain periodic alternating superlattices on the surface evolution during the growth of semi-polar (11-22) InGaN light-emitting diodes. Semi-polar (11-22) light-emitting diodes were grown on different templates with and without AlN/GaN strain periodic alternating superlattices. A direct correlation between the surface evolution, crystal quality, and optical properties was demonstrated, suggesting higher indium adsorption with increased crystallinity. Moderate indium flux induced lower surface undulation with intensified photoluminescence emission in the green range. Substantial improvement in the crystal quality of semi-polar (11-22) InGaN light-emitting diode was achieved using AlN/GaN strain periodic alternating superlattice. A sample with an AlN/GaN strain periodic alternating superlattice had the lowest terrace size density of 400 nm(2), indicating a homogeneous terrace size distribution. In addition, the AlN/GaN template improved the optical properties, red shifting the photoluminescence to almost 15 nm from 495 nm (without superlattices). These findings demonstrate the potential of obtaining high indium adsorption semi-polar light-emitting diodes on large-scale sapphires with inexpensive feasibility. |
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