Simulation

Matlab Calculations

Thermal conductivity within gallium nitride nanomembranes of different thicknesses:

As the nanomembrane's thickness decreases, less than the phonon mean free path in GaN (~100 nm), the effect of phonon-boundary scattering increases. Thus, the phonon lifetime decreases and the thermal conductivity of the structure decreases.

Bandgap modulation within wrinkled gallium nitride nanomembranes:

Due to the extremely low flexural rigidity of nanomembranes, external compressive strain produces wrinkles within the structures. Wrinkled and flat regions have different internal strains and thus have different photoluminescence

COMSOL Simulations

Temperature distribution due to laser heating within a nanomembrane attached to a single cell:

As a 325 nm laser beam with 4mW of power and 80 microsecond pulse width is focused on the surface of the nanomembrane, the photo-excited carriers relax through multiple phonon emissions. Due to the increase phonon-boundary scattering, the local phonon density increases causing an increase in local temperature.

Temperature distribution within electrically injected nanowires on Molybdenum, Silicon and Sapphire:

Heating within GaN nanowires occurs during electrical injection. While sapphire prevents heat dissipation and thus causes device degradation, other substrate materials such as silicon and molybdenum offer better heat dissipation.

3Ds Max Design

Nanomembrane-based thermal biosensor for living cells.

After the nanomembrane is attached to a living cell, a pulsed excitation laser is used to heat the nanomembrane. As heat energy gets dissipated through the cell, the nanomembrane temperature, which affects its photoluminescence, becomes a function of the cell's thermal properties.

Exfoliation of gallium nitride nanomembranes:

During the etching of Gallium nitride nanomembranes, nanowires form within the porous layer that extend all the way through the etch pits within the nanomembrane.

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