Electrical and physical characterization of the Al₂O₃/ <i>p</i>-GaSb interface for 1%, 5%, 10%, and 22% (NH₄)₂S surface treatments

In this work, the impact of ammonium sulfide ((NH&lt;sub&gt;4&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;S) surface treatment on the electrical passivation of the Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;/ &lt;i&gt;p&lt;/i&gt;-GaSb interface is studied for varying sulfide concentrations. Prior to atomic layer deposition of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;, GaSb surfaces were treated in 1%, 5%, 10%, and 22% (NH&lt;sub&gt;4&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;S solutions for 10 min at 295 K. The smallest stretch-out and flatband voltage shifts coupled with the largest capacitance swing, as indicated by capacitance-voltage (&lt;i&gt;CV&lt;/i&gt;) measurements, were obtained for the 1% treatment. The resulting interface defect trap density (&lt;i&gt;D&lt;/i&gt;&lt;sub&gt;it&lt;/sub&gt;) distribution showed a minimum value of 4 x 10&lt;sup&gt;12&lt;/sup&gt; cm&lt;sup&gt;-2&lt;/sup&gt;eV&lt;sup&gt;-1&lt;/sup&gt; at &lt;i&gt;E&lt;/i&gt;&lt;sub&gt;v&lt;/sub&gt; + 0.27 eV. Transmission electron microscopy and atomic force microscopy examination revealed the formation of interfacial layers and increased roughness at the Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;/ &lt;i&gt;p&lt;/i&gt;-GaSb interface of samples treated with 10% and 22% (NH&lt;sub&gt;4&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;S. In combination, these effects degrade the interface quality as reflected in the &lt;i&gt;CV&lt;/i&gt; characteristics

In-situ characterization of Ga2O passivation of In0.53Ga0.47As prior to high-k dielectric atomic layer deposition

Ga2O interfacial passivation layers (IPLs) on In0.53Ga0.47As are investigated using in-situ monochromatic x-ray photoelectron spectroscopy. The oxide is entirely composed of Ga2O when deposited with an effusion cell temperature of 1500 degrees C and substrate temperature of 425 degrees C. The growth on In0.53Ga0.47As reveals slight chemical modification of the surface. The Ga2O behavior and ability to protect the III-V surface are observed following Al2O3 deposition by atomic layer deposition following each precursor pulse. Al2O3 growth by trimethyl-Al (TMA) and water reveals that the IPL undergoes the "clean-up" effect following TMA exposures causing As-As bonding formation resulting in a high interface state density. (C) 2011 American Institute of Physics. (doi:10.1063/1.3615666

Healthy Vegan Lifestyle Habits among Argentinian Vegetarians and Non-Vegetarians

Although current research has contributed to the promotion of whole-food plant-based diets, few studies have examined healthy vegan dietary and lifestyle factors, especially in South America. Therefore, we aimed at investigating the adherence to healthy vegan lifestyle habits among Argentinian vegetarians and omnivorous, using a recently developed vegetarian lifestyle index adapted to the vegan dietary pattern. Also, accessibility of vegetarian foods, and the proportion of household income spent on food were assessed in a cross-sectional approach with 1454 participants. The population was comprised of females (84.9%), singles (55.0%), young-adults (mean age 32.1, standard deviation (SD) = 13.6), employed (50.8%), with high educational levels (50.4%), and low prevalence of both tobacco smoking (7.0%) and frequent alcohol consumption (7.6%). The mean score of adherence to healthy vegan lifestyle habits was 6.64 (SD = 1.72), with higher scores indicating better adherence. Non-vegetarians (5.75; 95% confidence interval (CI), 5.61&ndash;5.89) had a significantly lower adjusted mean score compared to semi-(6.32; 95% CI, 6.17&ndash;6.47), pesco-(6.99; 95% CI, 6.59&ndash;7.39), lacto-ovo-vegetarians (7.10; 95% CI, 6.96&ndash;7.24), as well as vegans (8.59; 95% CI, 8.35&ndash;8.83). The mean proportion of household income spent on food was significantly lower among vegans compared with other dietary patterns. The whole studied population showed a low consumption of whole grains, legumes, vegetables, nuts, and seeds. Although vegans showed a better diet and lifestyle pattern there is a need to improve eating and lifestyle habits to address risk factors for non-communicable diseases in Argentina

A multinomial model for the quality control of colony counting procedures

The so-called good-laboratory-practice (GLP) test provides an experimental design and appropriate statistical analysis for the problem of analyst performance assessment in microbiological laboratories. For a given sample material multiple dilution series are generated yielding colony counts from several dilution levels. Statistical evaluation is based on the assumption of Poisson-distributed colony forming units. In this paper a new model based on conditional binomial and multinomial distributions is presented and it is shown how it is related to the standard model which assumes Poisson-distributed colony counts. The effects of common working errors on the statistical evaluation of the GLP-test are investigated. (orig.)Available from TIB Hannover: RR 8460(1999,19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman