Resistance type behavior

The poly-Si films obtained by ALILE process always show p-type behavior. On high temperature resistant foreign substrates, the p-type poly-Si can be transferred to n-type poly-Si by overdoping, e.g., by phosphorous diffusion at 950°C [68], This allows for other solar cell configurations (e.g., substrate/ n+-type ALILE seed layer/n-type absorber/p+-type emitter). 

However for intermediate compositions (32-50% in CHDM) they formed homogeneous mixtures above an upper critical solution temperature (UCST) that rendered a miscible metastable phase upon quenching. A thermodynamic analysis of the USCT-type behavior demonstrated that the bare interaction energy for each pair of blends, was positive and increased with the content of 1,4-CHDM units in the copolymer (140). Commercial PEj.C -T/ PC blends (Ektar DA series, Eastman Kodak) have been used in lawn and garden equipment, floor care appliance parts, sterilizable medical equipment, etc. In these applications, a beneficial combination of clarity, toughness, chemical resistance, heat, UV and gamma radiation resistance has been profited. Molded parts made of these blends generally showed excellent surface finish and hence molded-in-color could be used (141). 

There have been no reported resistivity data for the hexagonal trihydrides although Wallace et al. (1963) reported that the resistivities of dysprosium and holmium hydrides increase by five orders of magnitude when these hydrides are fully hydrogenated. Singh et al. (1976) found semiconductor-type behavior for erbium trihydride. It is generally believed that the hexagonal rare earth hydrides are semiconductors. 

The PTCR effect is complex and not fully understood in terms of the grain boundary states and stmcture. Both the PTCR effect and room temperature resistivities are also highly dependent on dopant type and ionic radius. Figure 11 (32) illustrates this dependence where comparison of the PTCR behavior and resistivity are made for near optimum concentrations of La ", Nd ", and ions separately substituted into BaTiO. As seen, lowest dopant concentration and room temperature resistivity are obtained for the larger radius cation (La " ), but thePTCR effect was sharpest for the smallest radius cation (Y " ), reflecting dual site occupancy of the Y " ion. 

---