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Description:
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Group III -Nitride semiconductors are currently under extensive investigation as promising materials for optoelectronic , high -temperature , and high -power devices due to properties such as large direct band gap , high thermal stability , and strong inter -atomic bonds . The performance of III -Nitride epitaxial devices depend heavily on their structural quality . Thin epitaxial semiconducting films usually contain high density of structural defects and a high degree of mosaicity ; the III -Nitrides in particular have these properties due to the lack of a natural substrate . In this thesis we study the mosaic nature of III -Nitride epitaxial layers and their characteristics like tilt angle , twist angle , interdependence factor (m ) . We also discuss methods to accurately determine the density of edge and screw dislocations in an epitaxial film .
In the latter part of the thesis we show the effect various growth parameters have on the structural and electrical properties of GaN : Mg , grown by MOCVD . The data for the study of GaN :Mg epitaxial layers was obtained using a high resolution X -ray diffractometer (XRD ) . Methods discussed earlier in the thesis were employed on the data to analyze critical structural information of the thin GaN films , with an ultimate aim of improving
their electrical , structural , thermal and optical properties . |