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Effects of background gases and pressure in pulsed laser deposition of Al-doped ZnO
摘要： Background gases (O2, He or Ar) with the pressure from ~ 10?3 Pa to 133.3 Pa are used in 355 nm laser deposition of Al-doped ZnO at room temperature. The effects of these gases and pressure on plasma formation are studied by optical emission spectroscopy (OES) and time of flight (TOF) measurement. The OES results show that the emission intensity of the species in O2 and Ar decrease slightly and then increase exponentially above ~ 5 Pa. The emission intensity in Ar is the highest, followed by emission in O2 whilst the emission in He is low and weakly depend on background gas pressure. TOF measurements indicate that the ion velocity decrease with increasing O2 and Ar pressure at about 5–10 Pa. The ion velocity is highest in He while the ion velocities in O2 and Ar are similar. Thin-film samples deposited in different gas at 2.6 Pa are amorphous, but those deposited at 133.3 Pa are crystalline and exhibit different morphologies and optical properties depending on type of gas. Samples deposited in O2 are highly transparent but those deposited in He and Ar contain nano and micron-sized structures with <50% transmittance. In addition, Zn crystallites are detected by X-ray diffraction.
关键词： Pulsed laser deposition,Background gases,Aluminum-doped zinc oxide,Pressure,Laser produced plasma,Nanostructured films
更新于2025-09-23 15:21:01
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Cu <sub/>2</sub> O porous nanostructured films fabricated by positive bias sputtering deposition
摘要： In this work, the authors fabricated Cu2O porous nanostructured films (PNFs) on glass slide substrates by the newly developed positive bias deposition approach in a balanced magnetron sputtering (MS) system. It was found that the surface morphology, crystal structure and optical property of the as-deposited products were greatly dependent on the applied positive substrate bias. In particular, when the substrate was biased at +50 and +150 V, both of the as-prepared Cu2O PNFs exhibited a unique triangular pyramids-like structure with obvious edges and corners and little gluing, a preferred orientation of (111) and a blue shift of energy band gap at 2.35 eV. Quantitative calculation results indicated that the traditional bombardment effects of electrons and sputtering argon ions were both negligible during the bias deposition in the balanced MS system. Instead, a new model of tip charging effect was further proposed to account for the controllable formation of PNFs by the balanced bias sputtering deposition.
关键词： positive bias deposition,balanced magnetron sputtering,Cu2O,porous nanostructured films
更新于2025-09-19 17:15:36
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Physical Vapor Deposited Films of a Perylene Derivative: Supramolecular Arrangement and Thermal Stability
摘要： The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 oC for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films.
关键词： perylene,PVD nanostructured films,thermal treatment,supramolecular arrangement
更新于2025-09-09 09:28:46