Atomic Force Microscopy Characterization of Nanocontacted III nitride Nanostructures
Type
ThesisAuthors
Almaghrabi, Latifah
Advisors
Ooi, Boon S.
Committee members
Ooi, Boon S.
Kosel, Jürgen

Alshareef, Husam N.

Program
Electrical EngineeringDate
2019-11Embargo End Date
2020-11-24Permanent link to this record
http://hdl.handle.net/10754/660270
Metadata
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At the time of archiving, the student author of this thesis opted to temporarily restrict access to it. The full text of this thesis will become available to the public after the expiration of the embargo on 2020-11-24.Abstract
A conductive atomic force microscopy (c-AFM) investigation of GaN nanostructures is reported for strain engineering optoelectronic and piezotronic devices. The use of AFM enables the simultaneous correlation between the surface morphology and charge carrier transport through the nanostructures. The samples under investigation are molecular beam epitaxy (MBE) grown InGaN/GaN nanowires on Ti coated Mo substrate and GaN nanowires on ITO. The metal-semiconductor interface between the metallic substrates and the GaN nanostructures form the bottom contact. A Pt-Ir coated AFM probe is used to create a Schottky top nano-contact. The two interfaces form a metal-semiconductor-metal (MSM) structure. Force and temperature-dependent IV curves are obtained and analyzed, and the MSM structure parameters are extracted. Modulation of both the conductivity and Schottky barrier height (SBH) is revealed. Drastic reduction of the barrier is observed to drive the junctions to ideal MSM under a combination of force and temperature, revealing a dynamic and controlled two-way switching of the devices from rectifying to ideal linear IV properties. Through compressive force modulation by AFM tip, a symmetric 80 meV reduction in SBH at ±0.7 V is realized for the sample grown on Mo. By a combination of temperature and force modulation, a 40 meV increase in SBH is achieved at 0.53 V for the sample on ITO. These results show that the formed structure is ideal for applications in optoelectronics, sensing, piezotronic, piezo-phototronic, and nano-energy harvesting devices.Citation
Almaghrabi, L. (2019). Atomic Force Microscopy Characterization of Nanocontacted III nitride Nanostructures. KAUST Research Repository. https://doi.org/10.25781/KAUST-6D851ae974a485f413a2113503eed53cd6c53
10.25781/KAUST-6D851