Fig. 7
a Illustration of ideal theory of III-nitride growth on 2D layer. The weak covalent bond caused by an interfacial 2D layer between overgrown layer and the substrate allows the exfoliation of overgrown layer. Subsequently, a used substrate can be recycled for saving a cost. b Typical two-step GaN growth condition on c-plane sapphire substrate for high crystal quality GaN using MOCVD. This reveals that III-nitride growth conditions such as high temperature, and toxic gases (H2 and NH3) may change the properties of 2D layer