High vertical yield InP nanowire growth on Si(111) using a thin buffer layer.

We demonstrate the growth of InP nanowires on Si(111) using a thin InP buffer layer. The buffer layer is grown using a two-step procedure. The initial layer formation is ensured by using a very low growth temperature. An extremely high V/III ratio is necessary to prevent In droplet formation at this low temperature. The second layer is grown on the initial layer at a higher temperature and we find that post-growth annealing of the buffer layer does not improve its crystal quality significantly. It is found that the layers inherently have the (111)B polarity. Nanowires grown on this buffer layer have the same morphology and optical properties as nanowires grown on InP (111)B substrates. The vertical yield of the nanowires grown on the buffer layer is over 97% and we also find that crystal defects in the buffer layer do not affect the morphology, vertical yield or optical properties of the nanowires significantly

InP-based radial heterostructures grown on [100] nanowires

© 2014 IEEE. InP-InxGa(1-x)As-InP quantum well tube (QWT) structures are grown on InP nanowires that are [100] oriented. The In mole fraction, x is varied between 0 and 1. The QWTs grown on the facets of the [100] nanowires that have {100} and {011} side facets forming an octagonal cross-section, are found to be highly non-uniform. Bright emission is observed at room temperature from these QWTs. Band-gap tunability in the near to mid-infrared region is achieved by controlling the thickness and composition of the quantum well

Influence of growth temperature and V/III ratio on Au-assisted In xGa1-xAs nanowires

InxGa1-xAs nanowires were grown using metal-organic chemical vapour deposition (MOCVD) with various growth temperatures and V/III ratios. The morphology of these nanowires and the composition distribution along the nanowire were studied as a function of these growth parameters. With higher growth temperature and lower V/III ratio, the tapering of the nanowires is reduced. However, the incorporation of Ga in the nanowires is also reduced with lower V/III ratio. The composition distribution along the nanowires is non-uniform with typically In-rich bases and Ga-rich tips. © 2012 IEEE

InP-In<inf>x</inf>Ga<inf>1-x</inf>As core-multi-shell nanowire quantum wells with tunable emission in the 1.3-1.55 μm wavelength range

© 2017 The Royal Society of Chemistry. The usability and tunability of the essential InP-InGaAs material combination in nanowire-based quantum wells (QWs) are assessed. The wurtzite phase core-multi-shell InP-InGaAs-InP nanowire QWs are characterised using cross-section transmission electron microscopy and photoluminescence measurements. The InP-InGaAs direct interface is found to be sharp while the InGaAs-InP inverted interface is more diffused, in agreement with their planar counterpart. Bright emission is observed from the single nanowires containing the QWs at room temperature, with no emission from the InP core or outer barrier. The tunability of the QW emission wavelength in the 1.3-1.55 μm communication wavelength range is demonstrated by varying the QW thickness and in the 1.3 μm range by varying the composition. The experiments are supported by simulation of the emission wavelength of the wurtzite phase InP-InGaAs QWs in the thickness range considered. The radial heterostructure is further extended to design multiple QWs with bright emission, therefore establishing the capability of this material system for nanowire based optical devices for communication applications

Tissue Culture, Genetic Engineering, and Nanotechnology in Bitter Gourd

Bitter gourd (Momordica charantia L.) belongs to the genus Momordica that includes 45 species. It is cultivated extensively in tropical, subtropical, and rarely under temperate climates. The plant is valued in various disciplines of life and natural sciences. It is extensively used for culinary purposes. Its extracts are important for the treatment of a number of diseases and ailments in traditional and modern medicinal systems because of the abundance of insulin-like peptides, a mixture of steroidal sapogenins and alkaloids. It is rarely used as an ornamental plant. There are very few reports on systematic research on agronomic, breeding, and biotechnological aspects that curtail the improvement of this crop plant. This chapter reviews available information on biotechnology in a bitter gourd that will help understand the current scenario and help in making plans for improvement of bitter gourd