Shallow optically active structural defect in wurtzite GaN epilayers grown on stepped 4H-SiC substrates

Title Shallow optically active structural defect in wurtzite GaN epilayers grown on stepped 4H-SiC substrates

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Significant progress has been achieved in making larger (2 inch) 4H-SiC substrates with much lower micropipe defect densities. With the recent availability of semi-insulating 4H-SiC substrates, the demonstration of impressive microwave power results have been made possible both in SiC MESFETs and in GaN/AlGaN HEMTs grown on these substrates. SiC MESFETs have achieved RF power densities of 4.6 W...

Structure of “star” defect in 4H-SiC substrates and epilayers

The structure of the “star” defect in 4H-SiC substrates and its effects on the extended defect structures in the epilayers were studied by molten KOH etching and transmission x-ray topography. Star defects consist of a center region with high densities of threading dislocations (both edge and screw types) and six arms of dislocation arrays extending along <11-20> directions. In addition, multip...

Depth-resolved cathodoluminescence study of zinc oxide nanorods catalytically grown on p-type 4H-SiC

Optical properties of ZnO nanorods (NRs) grown by vapour-liquid-solid (VLS) technique on 4Hp-SiC substrates were probed by cathodoluminescence (CL) measurements at room temperature and at 5 K complemented with electroluminescence. At room temperature the CL spectra for defect related emission intensity was enhanced with the electron beam penetration depth. We observed a variation in defect rela...

Strain relaxation in GaN grown on vicinal 4H-SiC(0001) substrates

The strain of GaN layers grown by Metal Organic Chemical Vapor Deposition (MOCVD) on three vicinal 4H-SiC substrates (0, 3.4 and 8 offcut from [0001] towards [11-20] axis) is investigated by X-ray Diffraction (XRD), Raman Scattering and Cathodoluminescence (CL). The strain relaxation mechanisms are analyzed for each miscut angle. At a microscopic scale, the GaN layer grown on on-axis substrate ...