Electronic quality

Loll, V. 1987 Load-Strength Modelling of Mechanics and Electronics. Quality and Reliability Engineering International, 3, 149-155. 

Doping is achieved by adding dopant gases such as phosphine, diborane, or trimethylboron to the silane [545-547]. The doped material is of electronic quality comparable to PECVD-doped material. 

As described earlier, the covalently bonded hydrogen, by passivating dangling bond defects and removing strained weak Si—Si bonds from the network, dramatically improves the semiconducting quality of amorphous silicon. Hence without the presence of hydrogen, effective amorphous semiconductor devices such as solar cells or thin film transistors would not be possible. Unfortunately, low defect density, high electronic quality... 

All gases used are of high quality. Nitrogen is of 99.999% and oxygen of 99.998% purity. Silicon tetrachloride4, germanium tetrachlorides and boron trichloride6 are of electronic quality. 

Westgard JO. Electronic quality control, the total testing process, and the total quality system. Clin Chim Acta 2001 307 45-8. 

Earlier work was carried out with crystalline bulk InP samples prepared by the gradient freeze method [274]. As In could become scarce due to its present use in electronics [275], the use of bulk material appears too expensive for appHcations. Therefore, homoepitaxial thin films have been prepared on InP wafers which can be removed by estabhshed Hft-off techniques [276]. The preparation by MOVPE allows scaling up and fine tuning of the growth process, enabhng fabrication of films with high electronic quality [277]. Besides the hitherto used (111) A-face (see Section 2.4.2.1), the surprisingly stable In-rich (100) surface is considered here. 

Low-cost semiconductor materials with appropriate bandgap and sufficient opto-electronic quality need to be identified and optimized to enable efficient solar energy absorption and charge extraction. 

The electronic quality of the layer was determined measuring the bulk minority carrier lifetime on a free-standing Si epitaxial layer passivated with a corona charged (Schofthaler et al. 1994) thermal oxide. From a measured Hall mobility of the holes of 186 cm A s, the bulk lifetime of (0.27 0.08) ps, a diffusion length of 11 pm for the electrons in the p-type Si could be estimated. The diffusion length of 11 pm was about double the epitaxial layer thickness of 5.8 pm. Therefore, the lAD method seemed suitable for the production of epitaxial Si solar cells (Krinke et al. 1999). 

Besides the stability issues encountered at the solid-liquid interface, its electronic quality defines the efficiency of the system. This encompasses the control of surface recombination but, also, the control of the energy band alignments between light absorbers, interfacial films, and electrocatalysts. Accordingly, two avenues have to be followed (i) the reduction of the surface recombination velocity (compare Eqs. 10,11,14) and (ii) the use of surface- or interface dipoles for band alignment tuning purposes. 

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