Semiconductor nanowire devices

Cao LY, White JS, Park JS, Schuller JA, Clemens BM, Brongersma ML (2009) Engineering light absorption in semiconductor nanowire devices. Nat Mater 8 643-647... 

One-dimensional (ID) nanostructures have also been the focus of extensive studies because of their unique physical properties and potential to revolutionize broad areas of nanotechnology. First, ID nanostructures represent the smallest dimension structure that can efficiently transport electrical carriers and, thus, are ideally suited for the ubiquitous task of moving and routing charges (information) in nanoscale electronics and optoelectronics. Second, ID nanostructures can also exhibit a critical device function and thus can be exploited as both the wiring and device elements in architectures for functional nanosystems.20 In this regard, two material classes, carbon nanotubes2131 and semiconductor nanowires,32"42 have shown particular promise. 

Fundamental aspects of vapor-liquid-solid (VLS) semiconductor nanowire growth are presented here. The synthesis of VLS semiconductor has been extended to different reaction media and pathways from the early chemical vapor deposition (CVD) approach, including solution-liquid-solid (SLS) and supercritical fluid-liquid-solid (SFLS), laser-catalyzed growth, and vapor-liquid-solid-epitaxy. The properties of nanowires grown by these VLS embodiments are compared. In this entry, VLS growth of nanowire heterostructures and oriented and hyperbranched arrays is examined. In addition, surface passivation and functionalization are assessed, and the importance of these techniques in the progress toward VLS produced nanowire devices is detailed. 

Crespilho, F.N., et al. Development of individual semiconductor nanowire for bioelectrochemical device at low overpotential conditions. Electrochem. Commun. 11(9), 1744-1747 (2009)... 

Devices like this have been used to detect binding events on CNTs and semiconductor nanowires. More recently, CNT FETs have been used to study enzyme motion at the single-molecule... 

For either conventional polycrystalline semiconductors or nanotubes and nanowires to be successful, the development of model and simulation tools that can be used for device and circuit design as well as for predictive engineering must be available. Since these devices are not necessarily based on single wires or single crystals, but rather on an ensemble of particles, the aggregate behavior must be considered. Initial efforts to provide the necessary physical understanding and device models using percolation theory have been reported.64,65... 

Nanowires and nanobelts of inorganic oxides have been fashioned into chemically sensitive semiconductor devices. These include tin and zinc oxides [9], and indium oxide [30], Once again, ammonia and NO2 gases were used for initial demonstrations. Oxygen had very little effect on the sensing action. Because of the low concentrations detected and the speed of the response, it was suggested that single-molecule response could be within reach with these ultraminiaturized sensors. 

Rolf Konenkamp is the Gertrude-Rempfer Professor of Physics at Portland State University in Portland, Oregon. His present research interests lie in the field of nanoscience. He has worked extensively on semiconductor devices, such as nanostructured solar cells and nanowire light-emitting diodes and transistors, and he holds several patents in this area. He has led the design and construction of a new high-resolution photoelectron microscope since 2002. This will be one of the first aberration-corrected microscopes of this type and it will be used to explore transport and confinement effects on the nanoscale. He has worked at NREL, HMI Berlin, Hitachi Tokyo, Princeton University and at the 1ST in Lisbon, and he is a member of the national R D team for thin-fUm photovoltaics in the US. 

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