title: Wet chemical etching induced stress relaxed nanostructures on polar & non-polar epitaxial GaN films.
abstract: We report formation of aligned nanostructures on epitaxially grown polar and nonpolar GaN films via wet chemical (hot H3PO4and KOH) etching. The morphological evolution exhibited stress relaxed faceted nanopyramids, flat/trigonal nanorods and porous structures with high hydrophilicity and reduced wettability. The nanostructured films divulged significant suppression of defects and displayed an enhanced intensity ratio of the near band edge emission to the defect band. Extensive photoemission analysis revealed variation in oxidation state along with elimination of OH-and adsorbed H2O molecules from the chemically modified surfaces. Fermi level pinning, and alteration in the surface polarity with substantial changes in the electron affinities were also perceived. The temperature dependent current-voltage analysis of the nanostructured surfaces displayed enhancement in current conduction. The in-depth analysis demonstrates that the chemically etched samples could potentially be utilized as templates in the design/growth of III-nitride based high performance devices.
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL Campus, Dr K. S. Krishnan Marg, New Delhi-110012, India. govind@nplindia.org and Advanced Materials and Devices, CSIR-National Physical Laboratory, Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Monu
authors.initials: M
authors.lastname: Mishra
authors.affiliation: Advanced Materials and Devices, CSIR-National Physical Laboratory, Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Abhiram
authors.initials: A
authors.lastname: Gundimeda
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL Campus, Dr K. S. Krishnan Marg, New Delhi-110012, India. govind@nplindia.org and Advanced Materials and Devices, CSIR-National Physical Laboratory, Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Shibin
authors.initials: S
authors.lastname: Krishna
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL Campus, Dr K. S. Krishnan Marg, New Delhi-110012, India. govind@nplindia.org and Advanced Materials and Devices, CSIR-National Physical Laboratory, Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Neha
authors.initials: N
authors.lastname: Aggarwal
authors.affiliation: Advanced Materials and Devices, CSIR-National Physical Laboratory, Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Bhasker
authors.initials: B
authors.lastname: Gahtori
authors.affiliation: Apex Level Standards & Industrial Metrology, CSIR-National Physical Laboratory (CSIR-NPL), Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Nita
authors.initials: N
authors.lastname: Dilawar
authors.affiliation: Enviromental & Biomedical Metrology, CSIR-National Physical Laboratory (CSIR-NPL), Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Ved Varun
authors.initials: VV
authors.lastname: Aggarwal
authors.affiliation: Apex Level Standards & Industrial Metrology, CSIR-National Physical Laboratory (CSIR-NPL), Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Manju
authors.initials: M
authors.lastname: Singh
authors.affiliation: Apex Level Standards & Industrial Metrology, CSIR-National Physical Laboratory (CSIR-NPL), Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Rajib
authors.initials: R
authors.lastname: Rakshit
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL Campus, Dr K. S. Krishnan Marg, New Delhi-110012, India. govind@nplindia.org and Advanced Materials and Devices, CSIR-National Physical Laboratory, Dr K. S. Krishnan Marg, New Delhi-110012, India.
authors.forename: Govind
authors.identifier: http://orcid.org/0000-0001-5006-7623
authors.initials: G
authors.lastname: Gupta