Efficacy of potassium salt of glyphosate on weed control and yield in transgenic corn

A field experiment was carried out at Directorate of Weed Research, Jabalpur for the consecutive two years during kharif 2009 and 2010 to evaluate the weed control efficiency and crop productivity with K salt of glyphosate formulation in field conditions. Treatments consisted of two transgenic stacked hybrids named Hishell and 900M Gold applied with glyphosate as early post-emergence at 900, 1 800 and 3 600 g a.i./ha during kharif season of 2010 with two conventional hybrids namely Proagro-4640 and HQPM-1. Among the treatments, early post-emergence application of glyphosate at all doses registered lower weed density and higher weed control efficiency, i.e. 100% in all transgenic corn hybrids at 21 DAS and at harvest. Significantly higher numbers of cobs/plot were observed in transgenic hybrids as compared to conventional entries. While more cob length was observed with Hishell Transgenic hybrids at all doses as compared to 900 M Gold transgenic hybrids. Hishell transgenic hybrids at 3 600 g/ha registered significantly higher number of grains per row as compared to with its conventional control, 900 M Gold transgenic hybrid (1 800g/ha), 900 M Gold conventional and national checks. Significantly higher values of 20 cob weight, 20 cob grain weight and total cob weight was observed with Hishell and 900 M Gold transgenic hybrids as compared to other conventional hybrid entries and national checks. Hishell and 900 M Gold transgenic hybrids performed better with regard to grain yield ranging between 6-10 tonnes/ha which was approximately 3 to 4 times higher than the average yield of maize crop per ha, i.e. 2.30 tonnes/ha during both the years. Hishell at all rates of glyphosate application performed equally well in terms of yield but the yield of 900 M Gold decreased as the dose was enhanced from 1 800 to 3 600 g/ha during second year of experimentation

Stress evaluation of RF sputtered silicon dioxide films for MEMS

377-381In the present work, the stress evaluation of RF sputtered silicon dioxide films for MEMS applications has been reported. The films were deposited in argon atmosphere in the pressure range 5-20 mtorr at 300 W RF power using a 3 inch diameter silicon dioxide target. The stress measurements were carried out using wafer curvature technique. All the deposited films show compressive stress except the film having thickness less than 5000 Å. It is observed that sputtering pressure, film thickness and annealing temperature affect the stress in SiO₂ films. The dependence of deposition rate and etch rate on the deposition parameters were also investigated. To obtain the minimum stress in the film, the deposition parameters are optimized. An array of cantilever beams of sputtered silicon dioxide film was fabricated. It was observed that beams up to 500 micron length show no upward or downward bending indicating low stress in the films deposited under optimized conditions

Effect of power on the growth of nanocrystalline silicon films

Nanocrystalline silicon thin films were grown using a gaseous mixture of silane, hydrogen and argon in a plasma-enhanced chemical vapor deposition system. These films were deposited away from the conventional low power regime normally used for the deposition of device quality hydrogenated amorphous silicon films. It was observed that, with the increase of applied power, there is a change in nanocrystalline phases which were embedded in the amorphous matrix of silicon. Atomic force microscopy micrographs show that these films contain nanocrystallite of 20–100 nm size. Laser Raman and photoluminescence peaks have been observed at 514 cm−1 and 2.18 eV, respectively, and particle sizes were estimated using the same as 8.24 nm and 3.26 nm, respectively. It has also been observed that nanocrystallites in these films enhanced the optical bandgap and electrical conductivity

RF power density dependent phase formation in hydrogenated silicon films

Hydrogenated amorphous and micro/nanocrystalline silicon films have been deposited using RF (13.56 MHz) PECVD technique in the RF power density range of 177 to 885 mW/cm2 exploiting SiH4 + H2 + Ar gaseous mixture. Predominant crystalline phase was observed in the films, as revealed from Raman spectroscopic study, deposited at power densities of 531 and 708 mW/cm2 and amorphous phase at 177, 354 and 885 mW/cm2. Amorphous to microcrystalline phase transition occurred near RF power density of 531 mW/cm2. The high crystalline phase (~ 80%) was found in the film deposited at 708 mW/cm2. Lower values of bond angle distortion of 6.7 and 5° were found for the films deposited at 531 and 708 mW/cm2 as compared to bond angle distortion of 8.4, 9.3 and 9.1° for the films deposited at 177, 354 and 885 mW/cm2, respectively. Plasma parameters extracted from V/I probe and properties of the films revealed contribution of ions to be beneficial for the enhancement of deposition rate of the films. The increased ion energy (sheath field) and ion flux together with SiHx (x = 1,2,3) radicals on growing film surface might help in the enhancement of crystallinity at 708 mW/cm2

Influence of argon dilution on growth and properties of hydrogenated nanocrystalline silicon films

The effect of argon concentration (66–87%) in total gaseous mixture (SiH4+H2+Ar) on growth and properties of hydrogenated nanocrystalline silicon films deposited by RF (13.56 MHz) PECVD technique was investigated. Raman and XRD measurements revealed increasing argon fraction favored enhancement of crystallinity, enlargement of crystallites and relaxation of strained bonds. Photoluminescence spectra of nc-Si:H films exhibited two radiative transitions in the photon energy ranges of 2.8–3.1 eV and 1.6–2.1 eV. The high energy PL peaks are attributed to surface effect of the films whereas peaks in the range of 1.6–2.1 eV are due to nanocrystallinity in the films. Argon dilution also helped enhancement of deposition rate and conductivity of the films. A film deposited at 81% of argon fraction possesses high crystallinity (75%), conductivity in the order of 10−5 (Ω cm)−1, size of the crystallite (Raman=12 nm, XRD=18 nm), and low residual stress (125 MPa)

High-pressure condition of SiH4+Ar+H2 plasma for deposition of hydrogenated nanocrystalline silicon film

The characteristics of 13.56-MHz discharged SiH4+Ar+H2 plasma at high pressure (2–8 Torr), used for the deposition of hydrogenated nanocrystalline silicon (nc-Si:H) films in a capacitively coupled symmetric PECVD system, has been investigated. Plasma parameters such as average electron density, sheath field and bulk field are extracted from equivalent circuit model of the plasma using outputs (current, voltage and phase) of RF V–I probe under different pressure conditions. The conditions of growth in terms of plasma parameters are correlated with properties of the hydrogenated nanocrystalline silicon films characterized by Raman, AFM and dc conductivity. The film deposited at 4 Torr of pressure, where relatively low sheath/bulk field ratio is observed, exhibits high crystallinity and conductivity. The crystalline volume fraction of the films estimated from the Raman spectra is found to vary from 23% to 79%, and the trend of variation is similar to the RF real plasma impedance data