Zirconium oxide (ZrO2) is a wide and direct band gap semiconductor used for the fabrication of optoelectronic devices. ZrO2 based optoelectronic devices span a wide optical range depending on the band gap of ZrO2 material. The band gap of ZrO2 can be tuned by fabricating it to the nanoscale. In this paper, we synthesized the ZrO2 nanostructures on quartz substrate using ZrO2 ions produced by the ablation of ZrO2 pellet due to high temperature, high density, and extremely non-equilibrium argon plasma in a modified dense plasma focus device. Uniformly distributed monoclinic ZrO2 nanostructures with an average dimension of ~14 nm were obtained through X-ray diffraction and scanning electron microscopy studies. The monoclinic phase of ZrO2 nanostructures is further confirmed from photoluminescence (PL) and Raman spectra. PL spectra show peaks in ultra-violet (UV), near-UV, and visible regions with tunable band gap of nanostructures. A similar tunability of band gap was observed from absorption spectra. The obtained structural, morphological, and optical properties are compared to investigate the potential applications of ZrO2 nanostructures in optoelectronic devices.

Abstract. Plasma route to nanofabrication has drawn much attention recently. The dense plasma focus (DPF) device is used for depositing aluminium nanoparticles on n-type Si (111) wafer. The plasma chamber is filled with argon gas and evacuated at a pressure of 80 Pa. The substrate is placed at distances 4.0 cm, 5.0 cm and 6.0 cm from the top of the central anode. The aluminium is deposited on Si wafer at room temperature with two focused DPF shots. The deposits on the substrate are examined for their morphological properties using atomic force microscopy (AFM). The AFM images have shown the formation of aluminium nanoparticles. From the AFM images, it is found that the size of aluminium nanoparticles increases with increase in distance between the top of anode and the substrate for same number of DPF shots. IntroductionAluminium is an important material for making contacts in silicon technology for its ability to make both ohmic and Schottky contacts [1]. It is possible to make ohmic contact by making the metal contacts to p-type regions and heavily doped n-type silicon regions and rectifying contact to lightly doped n-type silicon regions. The need for low temperature processing and low resistive material in IC technology has made this simple metal contacts widely used in large scale integration (LSI) and also in early stage of the very large scale integration (VLSI) in recent times. Nanostructures like aluminium silicon nanowire networks have also been fabricated on glass and Si substrates by dealloying an Al-Si thin film through selective chemical etching [2] in order to miniaturize and make power efficient devices. Nanowire can act as electron confinement structure. When it is coupled with appropriate self configuring computer control architecture it would enable realization of self assembled ultrahigh density electronic device. So, metallic contacts of atomic dimensions have been a subject of interest in recent times. Plasma aided nanofabrication [3][4][5][6] has been considered widely for material deposition. Many techniques such as ionized cluster beam (ICB), partially ionized beam (PIB) [7], electron beam evaporation [8], magnetron sputtering [9], pulsed microarc discharge [10] techniques have been employed to deposit aluminium on different substrates. ICB technique has a limitation that the requirement of using a small nozzle of the order of 1-2 mm for supersonic

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Luminescent ZnO nanoparticles have been synthesized on silicon and quartz substrates under extremely non-equilibrium conditions of energetic ion condensation during the post-focus phase in a dense plasma focus (DPF) device. Ar+, O+, Zn+ and ZnO+ ions are generated as a result of interaction of hot and dense argon plasma focus with the surfaces of ZnO pellets placed at the anode. It is found that the sizes, structural and photoluminescence (PL) properties of the ZnO nanoparticles appear to be quite different on Si(1 0 0) and quartz substrates. The results of x-ray diffractometry and atomic force microscopy show that the ZnO nanoparticles are crystalline and range in size from 5–7 nm on Si(1 0 0) substrates to 10–38 nm on quartz substrates. Room-temperature PL studies reveal strong peaks related to excitonic bands and defects for the ZnO nanoparticles deposited on Si (1 0 0), whereas the excitonic bands are not excited in the quartz substrate case. Raman studies indicate the presence of E2 (high) mode for ZnO nanoparticles deposited on Si(1 0 0).