Sneha Rhode

Morphological, structural, and emission characterization of trench defects in InGaN/GaN quantum well structures

In a wide variety of InGaN/GaN quantum well (QW) structures, defects are observed which consist of a trench partially or fully enclosing a region of the QW having altered emission properties. For various different defect morphologies, cathodoluminescence studies suggest that the emission is redshifted in the enclosed region. Based on transmission electron microscopy and atomic force microscopy data, we suggest that the sub-surface structure of the trench defect consists of a basal plane stacking fault bounded by a stacking mismatch boundary, which terminates at the apex of a V-shaped trench.

Segregation of in to dislocations in InGaN

Dislocations are one-dimensional topological defects that occur frequently in functional thin film materials and that are known to degrade the performance of InxGa1-xN-based optoelectronic devices. Here, we show that large local deviations in alloy composition and atomic structure are expected to occur in and around dislocation cores in InxGa(1-x)N alloy thin films. We present energy-dispersive X-ray spectroscopy data supporting this result. The methods presented here are also widely applicable for predicting composition fluctuations associated with strain fields in other inorganic functional material thin films.

Carrier localization in the vicinity of dislocations in InGaN

This project is funded in part by the European Research Council under the European Communitys Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement No. 279361 (MACONS). The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483-ESTEEM2 (Integrated Infrastructure InitiativeI3). F.M. would also like to acknowledge the financial support from EPSRC Doctoral Prize Awards and Cambridge Philosophical Society. M.H. would like to acknowledge support from the Lindemann Fellowship.

Solid phase epitaxial growth of high mobility La:BaSnO3 thin films co-doped with interstitial hydrogen

This work presents the solid phase epitaxial growth of high mobility La:BaSnO3 thin films on SrTiO3 single crystal substrates by crystallization through thermal annealing of nanocrystalline thin films prepared by pulsed laser deposition at room temperature. The La:BaSnO3 thin films show high epitaxial quality and Hall mobilities up to 26 ± 1 cm2/Vs. Secondary ion mass spectroscopy is used to determine the La concentration profile in the La:BaSnO3 thin films, and a 9%–16% La doping activation efficiency is obtained. An investigation of H doping to BaSnO3 thin films is presented employing H plasma treatment at room temperature. Carrier concentrations in previously insulating BaSnO3 thin films were increased to 3 × 1019 cm−3 and in La:BaSnO3 thin films from 6 × 1019 cm−3 to 1.5 × 1020 cm−3, supporting a theoretical prediction that interstitial H serves as an excellent n-type dopant. An analysis of the free electron absorption by infrared spectroscopy yields a small (H,La):BaSnO3 electron effective mass of 0....

Electron effective mass and mobility limits in degenerate perovskite stannateBaSnO3

The high room temperature mobility and the electron effective mass in BaSnO

Dislocations in AlGaN: Core Structure, Atom Segregation, and Optical Properties

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Band gap bowing in NixMg1-xO.

are investigated in depth by evaluation of the free carrier absorption observed in infrared spectra for epitaxial films with free electron concentrations from

Towards a better understanding of trench defects in InGaN/GaN quantum wells

8.3 \times 10^{18}

Alloy fluctuations at dislocations in III-nitrides: identification and impact on optical properties

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Research data supporting "Dislocations in AlGaN: core structure, atom segregation and optical properties"

7.3 \times 10^{20}