Question

Why is a substrate needed in growing GaN?

Answer 1

Crystal growth always needs a substrate. You need a template, which tells the atoms how to arrange. Ideally, the substrate would have the same crystal structure and lattice constant. Since GaN substrates were technologically different to realize, growth on sapphire or Si(111) was studied.

A special case for GaN growth is called lateral epitaxial overgrowth, where an oxide mask prevents growth in large areas and allows only growth in between. For proper conditions, GaN first fills up the holes and then overgrows the mask and great s a virtual GaN substrate with lower defect densities.




HOPEFULLY MARK AS BRAINLIEST

Answer 2

Hey !

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substrates are produced by growing epitaxial layers on the Large bulk gallium nitride (GaN) single crystal substrates with low dislocation density are the key material.

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Thanks !