Stable Defects in Semiconductor Nanowires
| Autor: | Huiyun Liu, H. A. Fonseka, James A. Gott, Richard Beanland, Ana M. Sanchez, Yunyan Zhang |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Materials science Condensed matter physics business.industry TK Mechanical Engineering Nanowire Shell (structure) Bioengineering Crystal growth 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure 01 natural sciences Null (physics) Dipole Semiconductor 0103 physical sciences General Materials Science 0210 nano-technology business QC Burgers vector |
| Zdroj: | Nano Letters. 18:3081-3087 |
| ISSN: | 1530-6992 1530-6984 |
| Popis: | Semiconductor nanowires are commonly described as being defect-free due to their ability to expel mobile defects with long-range strain fields. Here, we describe previously undiscovered topologically protected line defects with null Burgers vector that, unlike dislocations, are stable in nanoscale crystals. We analyze the defects present in semiconductor nanowires in regions of imperfect crystal growth, i.e., at the nanowire tip formed during consumption of the droplet in self-catalyzed vapor-liquid-solid growth and subsequent vapor-solid shell growth. We use a form of the Burgers circuit method that can be applied to multiply twinned material without difficulty. Our observations show that the nanowire microstructure is very different from bulk material, with line defects either (a) trapped by locks or other defects, (b) arranged as dipoles or groups with a zero total Burgers vector, or (c) have a zero Burgers vector. We find two new line defects with a null Burgers vector, formed from the combination of partial dislocations in twinned material. The most common defect is the three-monolayer high twin facet with a zero Burgers vector. Studies of individual nanowires using cathodoluminescence show that optical emission is quenched in defective regions, showing that they act as strong nonradiative recombination centers. |
| Databáze: | OpenAIRE |
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