Growth of Gallium Nitride Nanorods and Their Coalescence Overgrowth
Abstract
With the nano-imprint lithography and the pulsed growth mode of metalorganic chemical vapor deposition, a regularly-patterned, c-axis nitride nanorod (NR) array of quite uniform geometry with simultaneous depositions of top-face, c-plane disc-like and sidewall, m-plane core-shell InGaN/GaN quantum well (QW) structures is formed. The differences of geometry and composition between these two groups of QW are studied with scanning electron microscopy, cathodoluminescence, and transmission electron microscopy (TEM). In particular, the strain state analysis results in TEM observations provide us with the information about the QW width and composition. It is found that the QW widths are narrower and the indium contents are higher in the sidewall m-plane QWs, when compared with the top-face c-plane QWs. Also, in the sidewall m-plane QWs, the QW width (indium content) decreases (increases) with the height on the sidewall. The observed results can be interpreted with the migration behaviors of the constituent atoms along the NR sidewall from the bottom. Besides, we demonstrate the growth of a conducting nitride layer of low vertical resistance (64 omega on 6H n-type SiC substrate. The nitride layer consists of a 150-nm n-AlGaN layer with the Al composition being linearly decreased from 20 to 0 % and a 1-micronmeter n-GaN layer. Both layers are Si doped with a level around 10(exp 18)/cu cm. The growth condition of the n-AlGaN layer must be further improved to obtain a crack-free and smooth surface.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 07, 2012
- Accession Number
- ADA566296
Entities
People
- Chih-Chung Yang
Organizations
- National Taiwan University