title: Micro Raman and photoluminescence spectroscopy of nano-porous n and p type GaN/sapphire(0001).
abstract: Variation of depth within a single etching spot (3 mm circular diameter) was observed in nanoporous GaN epilayer obtained on photo-assisted electrochemical etching of n and p-type GaN. The different etching depth regions were studied using microRaman and PL(yellow region) for both n-type and p-type GaN. From Raman spectroscopy, we observed that increase in disorder is accompanied by stress relaxation, as depth of etching increases for n-type GaN epilayer. This is well corroborated with scanning electron microscopy results. Contrarily, for p-type GaN epilayer we found that for minimum etching depth, stress in epilayer increases with increase in disorder. This is understood with the fact that as grown p-type GaN is more disordered compared to n-type GaN due to heavy Mg doping and further disorder leads to lattice distortion leading to increase in stress.
authors.affiliation: Laser Physics Application Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India.
authors.forename: Alka
authors.initials: A
authors.lastname: Ingale
authors.forename: Suparna
authors.initials: S
authors.lastname: Pal
authors.forename: V K
authors.initials: VK
authors.lastname: Dixit
authors.forename: Pragya
authors.initials: P
authors.lastname: Tiwari
mesh_terms: D003460:Crystallization / Q000379:methods; D005708:Gallium / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D016062:Porosity; D045663:Quantum Dots; D012666:Semiconductors; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; C473348:gallium nitride; D005708:Gallium