Lattice-Asymmetry-Driven Selective Area Sublimation: A Promising Strategy for III-Nitride Nanostructure Tailoring

Lattice-asymmetry-driven selective area sublimation (SAS) process of GaN is systemically investigated by exploring the in situ dynamic evolution of the decomposition pathway under ultra-high vacuum. The rationale of the SAS is confirmed as a strong anisotropic decomposition driven by lattice-asymmetry of wurtzite crystal: the sublimation preferably starts along the -c axis due to the relatively lower decomposition energy barrier. Finally, the fabrication of site- and size-controlled GaN nanowires has been achieved by utilizing the SAS process, exhibiting good controllability on the sidewall of nanowires. These findings shed light on the thermodynamic mechanism of the lattice-asymmetry-driven sublimation process in III-nitrides, providing an efficient alternative approach for the tailoring of semiconductor micro/nanostructures.