Near field imaging of gallium nitride nanowires for characterization of minority carrier diffusion

Download
Author
Baird, Lee G.
Date
2009-12Advisor
Haegel, Nancy M.
Second Reader
Luscombe, James
Metadata
Show full item recordAbstract
A novel system has been developed for the imaging of carrier transport within semiconductor nanostructures by operating a near field scanning optical microscopy (NSOM) within a scanning electron microscope. Luminescence associated with carrier recombination is collected with high spatial resolution to monitor the motion and recombination of charge generated by use of an electron beam as an independent point source. Light is collected in the near field from a scanning fiber using tuning fork feedback in an open architecture combined AFM/NSOM system allowing for independent motion of sample and tip. From a single image, it is possible to obtain a direct measure of minority carrier diffusion length. This technique has been used in the near-field collection mode to image the diffusion of holes in n-type GaN-AlGaN coreshell nanowires, unintentionally doped GaN nanowires and p-type GaN nanowires grown via Ni-catalyzed MOCVD. Measurements were made on tapered anowires ranging in diameter from 500 to 800 nm, with lengths up to ~ 30 ?m. The average 1-dimensional carrier diffusion length was measured to be 1.3 +/- 0.2 ?m for GaN/AlGaN core-shell, 0.96 +/- 0.25 ?m for the uncoated GaN wires, and 0.65 +/- 0.35 ?m for the p-tpye uncoated GaN anowires in the low injection limit.
Related items
Showing items related by title, author, creator and subject.
-
Near field imaging of charge transport in gallium nitride and zinc oxide nanostructures
Cole, Richard Adam (Monterey, California. Naval Postgraduate School, 2010-12);A novel technique for imaging minority carrier diffusion in semiconductor nanostructures has been applied to the characterization of GaN and ZnO nanowires and nanobelts. Near field scanning optical microscopy (NSOM) is ... -
Measurement of minority charge carrier diffusion length in Gallium Nitride nanowires using Electron Beam InducedCurrent (EBIC)
Ong, Chiou Perng (Monterey, California. Naval Postgraduate School, 2009-12);Electron Beam Induced Current (EBIC) measurements were performed on GaN nanowires to determine minority charge carrier diffusion length, d L . Although EBIC has been used to characterize bulk and thin film materials, ... -
Near Field Imaging for the Characterization of Diffusion Length and Waveguiding in Zinc Oxide Nanowires
Little, Anree G. (Monterey, California. Naval Postgraduate School, 2012-06);A novel technique of near field imaging has been advanced and used to measure free carrier diffusion length and study optical waveguiding in ZnO nanowires. The technique employs a near field scanning optical microscope ...