Among other group III-nitride semiconductor materials, gallium nitride (GaN) has received considerable attention for fabricating optical devices mainly in the UV region. [1] Along with this for fabricating a number of electronic gadgets, for example, high-power and high-frequency devices, [2] high-speed data transmitters, [3] high-voltage switching devices, [4,5] etc., extensive use of GaN is also well known. This demonstrates that GaN as a material has not only received special attention by the scientific community but also acknowledged due to its commercial importance. It's high electron saturation velocity (%1 Â 10 7 cm s À1 ), greater breakdown field than the Si, [6] and sustainability to work at high operating temperatures are key to realize such applications. The material has a wide bandgap of %3.4 eV at 300 K. [6] Excellent solubility with the other III-nitride semiconductor materials especially InN and AlN has enabled researchers to tune the bandgap of a material as per requirement. Hence in the past few years, GaN is extensively used to fabricate optoelectronic devices such as high-power light-emitting diodes. [7] Most of these devices are demonstrated using epitaxial films of GaN grown along c-axis, that is, [1] orientation. The performance and the efficiency of these devices mainly depend on the quality growth of GaN films with suitable dopants incorporated to have better control on its physical properties. Mostly epitaxial growth of GaN on GaN substrate is preferred but it is extremely expensive. Hence, epitaxial growth of GaN on low-cost substrates, for example, sapphire, Si, etc., for its commercial uses is justifiable. To grow epitaxial films of GaN on sapphire conventional methods, for example, molecular beam epitaxy (MBE), [1] metal-organic chemical vapor deposition (MOCVD), [8] atomic layer deposition (ALD), [9] metal-organic vapor-phase epitaxy (MOVPE) [10] are preferably used due to their due advantages. The use of a pulsed laser deposition (PLD) for growing GaN films is also demonstrated, taking its unique capabilities into consideration. [11,12] However, it is observed that optoelectronic devices fabricated using c-plane GaN suffer from piezoelectric polarization effect, affecting the carrier recombination lifetime and quantum efficiency of devices known as quantum conferment Stark effect. [13] Avoiding the Stark effect quality growth of GaN films along nonpolar surfaces is suggested. Hence, researchers are intensively studying the growth of GaN films along nonpolar surfaces such as m-and a-planes. [13][14][15] Mostly growth of a-plane GaN using r-plane sapphire, (010) LAO substrate, etc. is widely
