Porosity-induced relaxation of strains in GaN layers studied by means of micro-indentation and optical spectroscopy
Type
ArticleKAUST Department
Advanced Membranes and Porous Materials Research CenterPhysical Science and Engineering (PSE) Division
Date
2012-05-04Online Publication Date
2012-05-04Print Publication Date
2012-05Permanent link to this record
http://hdl.handle.net/10754/552828
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We report the fabrication of porous GaNnanostructures using UV-assisted electroless etching of bulk GaN layer grown on c-plane sapphire substrate in a solution consisting of HF:CH3OH:H2O2. The morphology of the porous GaNnanostructures was characterized for different etching intervals using high resolution scanning electron microscopy. The geometry and size of resultant pores do not appear to be affected by the etching time; however, the pore density was augmented for longer etching time. Micro-indentation tests were carried out to quantify the indentation modulus for different porous GaNnanostructures. Our results reveal a relationship between the elastic properties and the porosity kinetics, i.e., a decrease of the elastic modulus was observed with increasing porosity. The photoluminescence(PL) and Raman measurements carried out at room temperature for the etched samples having a high degree of porosity revealed a strong enhancement in intensity. Also, the peak of the PL wavelength was shifted towards a lower energy. The high intensity of PL was correlated to an increase of scattered photons within the porous media and to the reduction of the dislocation density.Citation
Porosity-induced relaxation of strains in GaN layers studied by means of micro-indentation and optical spectroscopy 2012, 111 (9):093513 Journal of Applied PhysicsPublisher
AIP PublishingJournal
Journal of Applied Physicsae974a485f413a2113503eed53cd6c53
10.1063/1.4710994