Abstract: A method for growing a non-polar a-plane gallium nitride includes cleaning of r-sapphire substrate, and nitridating for initiating growth sequences. The growth sequences include growing a gallium nitride nucleation layer, growing a thick first layer of gallium nitride, growing a film stack of gallium nitride and aluminum nitride as a superlattices layer, and overgrowing of gallium nitride on superlattices layer to form a second layer. The non-polar a-plane gallium nitride is grown by inserting multiple layers of a gallium nitride and an aluminum nitride for improving lateral surface morphology of gallium nitride on r-sapphire substrate.

Abstract: A method for growing a semi-polar gallium nitride epitaxial layer by inserting aluminum nitride and gallium nitride multi-layers includes the steps of cleaning m-sapphire substrates and activating the m-sapphire substrates by utilizing a combination of precursors and carrier gas. The method of growing a layer of semi-polar gallium nitride epitaxial layer on m-sapphire substrates further includes nitridating for initiating growth sequence and depositing a nucleation layer. The film stack of aluminum nitride and gallium nitride multi-layers is grown to initiate growth of a super lattice layer on m-plane sapphire substrates. Subsequently, a layer of the undoped gallium nitride is deposited on the m-plane sapphire substrate.

Abstract: A method of depositing a coating layer comprising gallium nitride on a substrate comprising the steps of: (a) providing the substrate having a plurality of side walls and valleys; (b) forming a first layer of gallium nitride deposited on the substrate, by reacting gaseous trimethylgallium and ammonia at a temperature ranging from 400 to 500° C., such that the first layer is formed on the side walls and the valleys; and (c) forming a second layer of gallium nitride deposited on top of the first layer, by reacting gaseous trimethylgallium and ammonia at a temperature ranging from 1000 to 1200° C., to obtain the coating layer comprising the first layer of gallium nitride and the second layer of gallium nitride at a thickness ranging from 3.0 to 4.5 ?m.

Abstract: A method of depositing a coating layer comprising gallium nitride on a substrate comprising the steps of: (a) providing the substrate having a plurality of side walls and valleys; (b) forming a first layer of gallium nitride deposited on the substrate, by reacting gaseous trimethylgallium and ammonia at a temperature ranging from 400 to 500° C., such that the first layer is formed on the side walls and the valleys; and (c) forming a second layer of gallium nitride deposited on top of the first layer, by reacting gaseous trimethylgallium and ammonia at a temperature ranging from 1000 to 1200° C., to obtain the coating layer comprising the first layer of gallium nitride and the second layer of gallium nitride at a thickness ranging from 3.0 to 4.5 ?m.