An electron paramagnetic-resonance study of diamond films doped by implantation of phosphorus during film deposition is reported. Samples with nominal phosphorus concentration between 1016 and 1017 cm−3 exhibit two isotropic lines of equal intensity separated by 27 G. The double-line spectrum is expected for a nuclear-spin 1/2 species such as phosphorus. The symmetry of the center and the temperature dependence of the spin concentration suggest that phosphorus forms a substitutional shallow donor in diamond.

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A model is proposed to explain disparities found in the operability values and histograms for long-wavelength infrared HgCdTe focal-plane arrays fabricated on Si substrates compared with those fabricated on CdZnTe. The starting point for the model is the close agreement between the aerial density of discrete species (particles, contamination spots, crystalline defects on Si surface) in various interfaces in the HgCdTe/CdTe/Si structure and the density of failed pixels in the array. The density of discrete species is acquired by applying a newly developed variation of the secondary-ion mass spectrometry (SIMS) depth-profiling technique to samples that have been deuterated to enhance detection. A mechanism of selective activation of threading dislocations in a HgCdTe layer on Si is proposed to link discrete species with failed detector pixels.

Thin-film superconductors of TIBaCaCuO (TBCCO) and YBaCuO (YBCO) were fabricated via an electrodeposition process. The precursors of the superconducting TBCCO films were codeposited at a constant potential of -4 V onto a silver-coated SrTiO 3 substrate. The YBCO precursors also were codeposited but under pulsed-potential conditions (in order to improve the film morphology) and onto a silver-coated MgO substrate. The pulsed-potential cycle consisted of 1 s at -4 V followed by 1 s at -1 V. The post-annealed TBCCO film showed zero resistance at about 102 K and critical current density at 76 K of 20 000 A/cm 2 in zero magnetic field and 5000 A/cm 2 in a 10 kOe field parallel to the film plane. The post-annealed YBCO film showed zero resistance at approximately 80 K and critical current density of 5160 A/cm 2 at 4 K in zero magnetic field.The electrodeposition of thin-film superconductors has considerable practical potential, particularly in the fabrication of large nonplanar devices as well as other electronic device applications. Electrodeposition has recently been used to fabricate high temperature thinfilm superconductors. 1 " 5 In principle, electrodeposition from both aqueous and nonaqueous solutions is possible, although aqueous solutions apparently are unsuitable because the reduction of water (-1.23 V vs NHE) is kinetically more favorable on most electrode materials (except Hg) than the alkaline metals ( < -2 . 0 V vs NHE). Information on the characteristics (structural, morphological, compositional, and electronic) of electrodeposited TBCCO and YBCO, and electrochemistry involved in the deposition process, however, is limited in the literature; therefore, we have undertaken a systematic study of these aspects in our laboratory. A summary of our findings to date is presented in this paper. Only one report of electrodeposited TBCCO by Maxfield et al? is available in the literature, and this describes the preparation of Tl-based superconductor films by sequential electrodeposition of the constituent metals. This method resulted in films with critical currents of 3000 A/cm 2 at 77 K in zero magnetic field. We report on the fabrication and properties of TBCCO and YBCO thin-film superconductors deposited from a single bath solution under constant potential and pulsed-potential conditions, respectively. The precursors of superconducting TBCCO and YBCO films are obtained by codeposition of constituent metals. We find a significant improvement in the critical current density (20 000 A/cm 2 at 76 K, zero field) of electrodeposited TBCCO superconductor film by using this codeposition technique. We have reported previously on YBCO and PbBiSrCaCuO thin-film superconductors electrodeposited under constant potential conditions. 4 ' 5 These films suffered from low critical current values due to weak link behavior and poor morphology. In an attempt to remedy this, a pulsed-potential deposition was used for YBCO film deposition in order to eliminate impurity phases and improve the film morphology. The critical current density...

Thin unoriented polycrystalline films in the Tl-Ca-Ba-Cu-O system were prepared by sequential electron beam evaporation of multiple Tl, Ca, Ba, and Cu layers and a two-stage anneal under controlled Tl and oxygen overpressures. These films show zero resistance as high as 97 K and transport critical current densities at 76 K up to 110 000 A/cm2 with typical values of 50 000 A/cm2. The critical currents exhibit a modest magnetic field dependence. Meissner effect data show an onset at 110 K and a superconducting fraction of 75%. Compositional and structural studies indicate that the films, although polyphase, are predominantly Tl2Ca1Ba2Cu2Oy. There is no evidence of other superconducting phases.