Amorphous silicon carbide solar cells fabricated using ECR-PECVD

Solar power is becoming important as an alternative energy source. Solar power generation utilizes solar cells, which generates DC electricity when light falls on them. Attractive materials for solar energy conversion are amorphous silicon (a-Si) and its alloys, such as amorphous silicon carbide (a-(SiC)). Although research on a-Si solar cells has been carried out in many countries since the 1970\u27s, a-(SiC) solar cells have not been widely studied. Amorphous silicon carbide has a wider bandgap than amorphous silicon; therefore, we can expect to have solar cells with larger open-circuit voltage and high conversion efficiency for the high-energy spectrum in tandem-cell arrangement. High bandgap combined with good material quality leads to an increase in open-circuit voltage. The work presented here explores the relationship between photovoltaic properties and growth conditions of amorphous silicon carbide solar cells. With this, we are able to determine a good fabrication technique for making a-SiC:H solar cells. In this thesis, we study film quality by measuring Urbach energy, E₀₄ and Tauc gaps, photo and dark conductivities, mobility-lifetime product, and activation energy.This report also studies the variation of these properties as functions of the growth conditions, such as substrate temperature, microwave power, chamber pressure, gas ratios, and doping levels. Then we applied the best growth conditions for making intrinsic and doped amorphous silicon carbide materials to produce good p-i-n solar cells. We found that a deposition pressure of 10 mTorr, a substrate temperatures of 300 to 350ðC, and CH₄/(CH₄+SiH₄) flows of 0.6 to 0.7 can produce very good amorphous silicon carbide solar cells. These solar cells have an open-circuit voltage of 0.96 V, and a fill factor of 0.71. We also found that our materials have superior quality compared to materials reported previously in the literature

Rapid Detection and Quantification of Mycobacterium Tuberculosis Using Single-Based Extension and Capillary Electrophoresis

In 1993, the World Health Organization (WHO) has declared tuberculosis (TB) a global emergency. Since then, more than 30 million lives have been claimed by that world-wide epidemic. In 2011, 8.7 million people “felt ill†because of TB and not all TB cases were reported to clinicians. Therefore, it is important to accurately identify TB patients by developing a diagnostic method that is sensitive, fast, and cost-effective. However, conventional methods have not met those criteria because they either require lengthy procedures or may misdiagnose TB cases. Hence, the automated Xpert MTB/RIF, endorsed by WHO in 2010, was developed and so far has been capable of quickly detecting TB and rifampicin resistant TB strains and producing test results in less than 100 minute. However, the Xpert MTB/RIF may leave out other drug-resistant TB strains which are equally important and in need of diagnoses. Therefore, we would like to utilize single-based extension and capillary electrophoresis (SBE-CE), a method that promises to identify all strains of Mycobacterium tuberculosis and possibly any mycobacterium. The main purpose of this study is to generate a calibration curve of the electrophoretic peak areas produced by CE versus the corresponding sample concentrations of DNA solutions. For initial proof of concept, algal DNA’s were also used to produce the calibration curves. The curves established a linear trend but with distinct slopes, possibly due to different fluorescent dyes used in SBE reactions

Formative Assessment in Teaching and Learning EFL

Formative assessment in EFL in Vietnam has previously been marginalized; however, there is now recognition of its important role for generating fair and reliable characterizations of students’ performances which cannot be solely made by summative assessments. The presenter will therefore draw attendees’ attention to distinctive features of formative assessment

ATLAS detector with cosmic rays and expected performance with early data

Cosmic muons have helped to understand the ATLAS detector in terms of DAQ, trigger, alignment and calibration. I briefly review the performance of the ATLAS Inner Detector, Calorimeters and Muon Spectrometer systems with cosmic rays. The expected performance with first LHC collisions will also be reviewed