Extended defects in GaN: Selective etching and optical properties

Contains fulltext : 26978_extedeing.pdf (publisher's version ) (Open Access)RU Radboud Universiteit Nijmegen, 26 september 2005Promotor : Larsen, P.K. Co-promotor : Weijher, J.X, 129 p

Statistical photoluminescence of dislocations and associated defects in heteroepitaxial GaN grown by metal organic chemical vapor deposition

Contains fulltext : 33011.pdf (publisher's version ) (Open Access

Defects in wide band-gap semiconductors: selective etching and calibration by complementary methods

Item does not contain fulltextTwo approaches to defect-selective etching used for revealing and analysis of defects in GaN and SiC are described and critically evaluated. These are: (i) orthodox etching which results in formation of pits on the defect sites and (ii) electroless etching, which yields protruding etch features. The mechanisms of surface reactions that are responsible for the distinct differences in the morphology of defect-related etch features are discussed. The most frequently used etching systems for GaN and SiC and the methods of verification of their reliability in revealing different types of defects are described

Etching, Raman and PL study of thick HVPE-grown GaN

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Influence of the nucleation layer morphology and epilayer structure on the resistivity of GaN films grown on c-plane sapphire by MOCVD

Contains fulltext : 32639.pdf (publisher's version ) (Closed access)The influence of hydrogen and nitrogen carrier gases used during the preparation of the nucleation layer on the structural and electrical properties of GaN layers has been investigated. The GaN were grown on sapphire substrates using metal organic chemical vapor deposition. The nucleation layer morphology strongly depends on the carrier gas affecting the electrical properties of GaN epitaxial films through changes of the ratio of edge to mixed and screw-type threading dislocations. X-ray diffractometry, X-ray reflectometry, atomic force microscopy, and defect selective etching were employed to study the structural properties of both the nucleation layer and the GaN epilayers deposited on top of this. It is found that the density of edge-type dislocations determines the resistivity of GaN epilayers and that one key factor for varying the density of these dislocations is the morphology of the nucleation layer, i.e. the morphology of the GaN epilayer can be controlled by the type of carrier gas used in the preparation of the nucleation layer. The electrical resistivity of our GaN epilayers is typically about 0.5Omegacm and more than 3 x 10(4) Omega cm with nucleation layers grown using hydrogen and nitrogen carrier gases, respectively. (C) 2004 Elsevier B.V. All rights reserved

Resistivity control of unintentionally doped GaN films

Contains fulltext : 32935.pdf (publisher's version ) (Closed access

Electrochemistry and etching of wide bandgap chemically resistant semiconductors

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Influence of the substrate misorientation of 4H-SiC substrates on the morphology and crack formation in hetero epitaxial MOCVD grown GaN epilayers by MOCVD

Contains fulltext : 32640.pdf (publisher's version ) (Closed access)4 p