We report on the epitaxial growth of wide-band-gap cubic-phase MgxZn1−xO thin films on Si(100) by pulsed-laser deposition and fabrication of oxide-semiconductor-based ultraviolet photodetectors. The challenges of large lattice and thermal expansion mismatch between Si and MgxZn1−xO have been overcome by using a thin SrTiO3 buffer layer. The heteroepitaxy of cubic-phase MgxZn1−xO on Si was established with epitaxial relationship of MgxZn1−xO(100)//SrTiO3(100)//Si(100) and MgxZn1−xO[100]//SrTiO3[100]//Si[110]. The minimum yield of the Rutherford backscattering ion channeling in MgxZn1−xO layer was only 4%, indicating good crystalline quality of the film. Smooth surface morphology with rms roughness of 0.6 nm was observed using atomic force microscopy. Photodetectors fabricated on Mg0.68Zn0.32O/SrTiO3/Si show peak photoresponse at 225 nm, which is in the deep UV region.

The phenomenon of persistent photoconductivity is elusive and has not been addressed to an extent to attract attention both in micro and nanoscale devices due to unavailability of clear material systems and device configurations capable of providing comprehensive information. In this work, we have employed a nanostructured (nanowire diameter 30–65 nm and 5 μm in length) ZnO-based metal–semiconductor–metal photoconductor device in order to study the origin of persistent photoconductivity. The current–voltage measurements were carried with and without UV illumination under different oxygen levels. The photoresponse measurements indicated a persistent conductivity trend for depleted oxygen conditions. The persistent conductivity phenomenon is explained on the theoretical model that proposes the change of a neutral anion vacancy to a charged state.

Over the past few years there has been sustained interest in the synthesis, characterization and application of cadmium sulphide (CdS) nanostructures such as nanoparticles, nanowires, nanobelts, nanospheres. The history of CdS, more recent advances in the chemistry and synthesis of CdS nanostructures, and their application as nanoscale devices in diverse technology areas from electronics to targeted drug delivery is described. Although the focus is on CdS, the review provides an excellent overview of the materials, methods, processes and promising solutions that are emerging.

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Pulsed-laser-deposited polycrystalline/amorphous films of mixed-valent manganites [La0.7Ca0.3MnO3 (LCMO), La0.5Sr0.5MnO3 (LSMO), La0.5Ba0.5MnO3 (LBMO), and (La0.6Pr0.4)0.67Ca0.33MnO3 (LPCMO)] grown at low temperature (450 °C) on single crystal (001) silicon substrate are evaluated for uncooled bolometric applications. It is shown that the temperature coefficient of resistance (TCR) and electrical noise (Sv) depend on the chemical composition. The optimum performance is found for LCMO with TCR of ∼7% K−1 and spectral noise ∼8.9×10−13 V2/Hz. In LBMO and LSMO the noise is much lower, but so is the TCR (1.5%–2% K−1). In LPCMO the TCR is high (∼10% K−1) and the noise is as well.

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The effects of hydrogen implantation on the structural and electrical properties of nickel silicide have been investigated. Ni films (30 nm) are electron-beam-evaporated on Si substrates, after which plasma immersion ion implantation is used to introduce hydrogen ions into the Ni films at an energy of 350 eV to a dose of 1×1016 cm−2. For nickel silicidation reactions, rapid thermal annealing is carried out in the range of 400-750°C for 30 s in a nitrogen atmosphere. It is shown that the implanted samples produce lower sheet resistances than the unimplanted samples across the whole annealing temperature range. X-ray diffraction results show that, regardless of the hydrogen implantation, NiSi is transformed into NiSi2 at temperatures in excess of 700°C. X-ray photoemission spectroscopy results show that the hydrogen implantation plays a role in reducing the nickel oxide layer. Compared to the unimplanted samples, the implanted samples exhibit better surfaces and uniform NiSi/Si interface morphologies. Transmission electron microscopy results show that the grain sizes of the implanted sample are smaller than those of the unimplanted sample. It is further shown that the implanted samples are thermally more stable than the unimplanted samples, which is attributed to the difference in the grain sizes of the nickel silicide films. © 2002 The Electrochemical Society. All rights reserved.

We have fabricated Zn1−xMgxO epitaxial thin-film composition spreads by layer-by-layer pulsed laser deposition (PLD) method where the composition across the chip is linearly varied from ZnO to MgO. In this paper we discuss the cross-sectional transmission electron microscopy study of the combinatorial spreads. The full orientation relationships between substrate and the ZnO and MgO phases were established. Formation of twin-related domain structure was found for the [111]-oriented MgO. Formation of the [100]-oriented cubic MgO in [0001]-oriented ZnO was observed in the mixed region in the middle of the spread. This relationship can potentially be used to grow [100]-oriented cubic structures epitaxially on c-axis-oriented hexagonal substrates. For the extended solid solution of ZnO, a high density of defects was found. Analysis of the defects established that they are translational domains formed by three-dimensional island growth of PLD and specific to the crystallography of ZnO. The ZnO phase appears without precipitation of the MgO phase, which supports the idea of extended substitutional solid solution.