The effect of the type of power cycle upon the amount of output electrical work for a pyroelectric converter has been measured. Output electrical energy densities are reported for ceramic lead zirconate modified with Sn4+ and Ti4+ in the execution of a variety of thermal-electrical cycles. The effect upon the energy density due to changes in the voltage cycle limits and changes in the load resistance were also studied. A conversion cycle which is an electric analog of the Ericsson cycle is shown to yield the largest output energy density (100 mJ/cm3 for a 12.6 K temperature excursion and a 28-kV/cm electric field excursion).

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Copolymers of vinylidene fluoride-trifluoroethylene P(VDF-TrFE) exhibit large piezoelectric ~Qd pyroelectric effects. In addition to the most common application of the pyroelectric effect (radiant detection) it is possible to'convert heat directly into electrical energy by pyroelectric conversion. This study reports the first pyroelectric conversion cycle to be measured. for the ------,copolymer-F(VDF-1=r:FE) .. It-isfound-that-standard-isotheimal-D-E-hysteresis-loopmeasurements--------are not necessarily accurate predictors of pyroelectric conversion performance for-this material. Conduction effects are found to obscure the observation of conversion cycles in most cases for the presently available materials. In spite of these difficulties, a conversion cycle was measured whose output electric energy density was 30 mJ/cm 3 • The output density isI5 times larger than any other polymer previously measured. -

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To investigate the mechanisms of hydrogen-induced blistering in III–V materials, a standard splitting dose of 5×1016H2+∕cm2 at 150keV was implanted into InP substrates cooled to −20°C. Substrate cooling during the implantation improved the reproducibility of this approach by limiting hydrogen mobility during ion implantation. The implant profile and defect structure of unbonded wafers were studied for various annealing schedules with double-axis x-ray diffraction and transmission electron microscopy. It was found that exfoliation was greatly facilitated by a combined lower-temperature (150°C) “defect nucleation” step, followed by a higher-temperature anneal (300°C). The nucleation of defects in the lower-temperature regime, which did not occur if the initial anneal was conducted only at higher temperatures, was attributed to defect trapping of hydrogen. This annealing sequence presents a means by which to (i) improve the interfacial bond strength at low temperatures while the “nucleation” occurs and (ii) promote efficient exfoliation at high temperature.