RESUMO
Gallium arsenide nanowires are grown on 100 GaAs substrates, adopting the epitaxial relation and thus growing with an angle around 35 degrees off the substrate surface. These straight nanowires are irradiated with different kinds of energetic ions. Depending on the ion species and energy, downwards or upwards bending of the nanowires is observed to increase with ion fluence. In the case of upwards bending, the nanowires can be aligned towards the ion beam direction at high fluences. Defect formation (vacancies and interstitials) within the implantation cascade is identified as the key mechanism for bending. Monte Carlo simulations of the implantation are presented to substantiate the results.
Assuntos
Arsenicais/química , Cristalização/métodos , Gálio/química , Nanotubos/química , Nanotubos/efeitos da radiação , Semicondutores , Arsenicais/efeitos da radiação , Gálio/efeitos da radiação , Íons , Substâncias Macromoleculares/química , Substâncias Macromoleculares/efeitos da radiação , Conformação Molecular/efeitos da radiação , Nanotecnologia/métodos , Nanotubos/ultraestrutura , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
We present a method which can be used for the mass-fabrication of nanowire photonic and electronic devices based on spin-on glass technology and on the photolithographic definition of independent electrical contacts to the top and the bottom of a nanowire. This method allows for the fabrication of nanowire devices in a reliable, fast, and low cost way, and it can be applied to nanowires with arbitrary cross section and doping type (p and n). We demonstrate this technique by fabricating single-nanowire p-Si(substrate)-n-ZnO(nanowire) heterojunction diodes, which show good rectification properties and, furthermore, which function as ultraviolet light-emitting diodes.
Assuntos
Eletrônica/instrumentação , Vidro/química , Nanotecnologia/instrumentação , Nanotubos/química , Fotoquímica/instrumentação , Silício/química , Óxido de Zinco/química , Cristalização/métodos , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Nanotecnologia/métodos , Nanotubos/ultraestrutura , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
Details of the vapour-liquid-solid Au droplet catalysed growth of ZnS nanobelts are elucidated in this work. The inclination of the Au droplet after solidification shows that it is indeed in the liquid state during nanobelt growth. Numerous stacking faults are observed when (0001) wurtzite is the side surface of the nanobelt. Compressive stress at the droplet-nanobelt-atmosphere triple interface is the cause of the stacking faults. Sawteeth-like structures are observed on the Zn-terminated polar (0001) side surface only. These surfaces are chemically active, while S-terminated [Formula: see text] surfaces and non-polar surfaces are not. On these active surfaces, autocatalysed vapour-solid growth leads to the formation of the observed sawteeth.
