Lateral patterning of GaN polarity using wet etching process

A lateral patterning of GaN polarity using wet etching process is demonstrated. The lattice polarity of a GaN film is examined by RHEED, KOH etching, micro-Raman scattering and Kelvin force microscopy investigations. We have confirmed the high crystal quality of the lattice-polarity inverted GaN heterostructure fabricated by the all-wet process. The difference between the surface potentials of the N-polar and Ga-polar GaN regions originates from the inversion of the direction of the spontaneous polarization as deduced from the fact that the piezoelectric polarization is negligible compared with the spontaneous polarization. The KOH etching result is consistent with the above mentioned result. This work is the first and direct demonstration for the successful fabrication of the polarity-inverted GaN heterostructure by an all-wet process. We suggest the feasibility of the convenient all wet process for the fabrication of the quasi-phase-matched waveguides and photonic crystals for efficient nonlinear frequency conversion