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CURATOR
A pinboard by
V M Ganesh Iyer

Research scholar in department of Materials science and Engineering in IITK.

I am interested in mechanics of materials in nanoscale, interface effects in nanostructures and their failure by fracture. Apart from sci-fi stuff mentioned above, I am an Indian and western classical music admirer, expedition enthusiast, and fauna fanatic.

PINBOARD SUMMARY

A FE algorithm is used to simulate the stress state of HEMT arising from several defects/conditions

In hetero-epitaxial systems interface effects gain prominence and the interplay of stress and defects determines the evolution of the system. During epitaxial growth the coherency stresses can be relaxed due to multiple mechanisms, which include: (i) the formation of a misfit interfacial edge dislocations, (ii) interfacial cracks and (iii) surface cracks.This section focusses in determining the critical sizes for the occurrence of these phenomena are determined from finite element simulations, via global energy criteria and local stress concentration effects. GaN/AlGaN and GeSi/Si systems are used as model systems for the computations. An interesting scenario, which combines epitaxy and phase transformation, is the case of precipitation in epitaxial films. A complex interaction exists between the multiple sources of stresses and the evolution of the system with growth. Keeping the abovementioned effects in view, the finite element methodology is extended to study the: (i) transition of the interface of the precipitate from a coherent to semi-coherent state, (ii) effect of geometry on critical thickness of epitaxial stripes, (iii) effect of periodicity in epitaxial superlattices and (iv) stress state of multilayer devices.