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Lift-off Process (lift-off + process)

Distribution by Scientific Domains
Physics and Astronomy60%

Selected Abstracts

Fabrication of free-standing ultrathin films of porous metal-organic frameworks by liquid-phase epitaxy and subsequent delamination

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 8-9 2010
Masih Darbandi
Abstract In this work we describe an approach to fabricate MOF (metal-organic framework) platelets with predefined shapes and well-defined thicknesses. The process is based on growing thin, highly oriented and ordered MOF films by selective liquid-phase epitaxy on prestructured organic substrates. In a second step, the MOF platelets are delaminated employing a lift-off process. The freestanding MOF platelets were characterized with TEM and SEM, which showed no evidence of fracture or deformation of the delaminated shapes. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Determination of the band-gap of MgS and MgS-rich Zn1,xMgxSySe1,y alloys from optical transmission measurements

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2010
Ian A. Davidson
Abstract As part of our development of an epitaxial lift-off process, utilising a sacrificial magnesium sulphide (MgS) layer, we have developed a MgS-rich ZnMgSSe alloy which provides excellent carrier confinement and resists both oxidation and acid attack. Here the optical transmission of the alloy has been measured and its bandgap determined as a direct transition at 4.19,±,0.04,eV. Its composition has also been determined by X-ray interference (XRI) and comparison with simulations. For a range of alloy samples we obtain compositions of the Zn1,xMgxSySe1,y layers which are (x, y),=,(0.80,±,0.02, 0.645,±,0.025). Using the alloy bandgap and composition we have determined direct bandgap transition energy for MgS by extrapolation. This is found to be 4.78,±,0.14,eV. [source]

Comparison of UV optical properties of ZnO nanoparticles dispersed in traditional organic and novel bio-molecular solvents

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2010
Liqiao Qin
Abstract Two types of ZnO nanoparticles were dispersed in a bio-molecular solvent and in ethanol. The mixtures were characterized by photoluminescence and absorbance measurements. Strong UV emission was observed near the band gap of ZnO at 380 nm. The parasitic green emission which normally appears in ZnO suspensions was weakened when ZnO was dispersed in the bio-molecular solvent. Suspensions were spin-cast on quartz, and then Al contacts were deposited by a standard lift-off process via e-beam lithography. Point contact current-voltage characteristics of the samples were measured under equal intensity conditions using 340 nm UV LED and white LED sources. The ratio of the UV photo-generated current to dark current was as high as 105. Finally, the photocurrent response spectrum was measured. The results show that ZnO nanoparticle is favourable for visible blind UV photodetectors. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Silicon thin-film solar cells with rectangular-shaped grating couplers

PROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 1 2006
H. Stiebig
Abstract As an alternative to randomly textured transparent conductive oxides as front contact for thin-film silicon solar cells the application of transparent grating couplers was studied. The grating couplers were prepared by sputtering of aluminium-doped zinc oxide (ZnO) on glass substrate, a photolithography and a lift-off process and were used as periodically textured substrates. The period size and groove depth of these transparent gratings were tuned independently from each other and varied between 1 and 4,,m and 100,600,nm. The optical properties of rectangular-shaped gratings and the opto-electronic behaviour of amorphous and microcrystalline silicon solar cells with integrated grating couplers as a function of the grating parameters (period size P and groove depth hg) are presented. The optical properties of the gratings are discussed with respect to randomly textured substrates and the achieved solar cell results are compared with the opto-electronic properties of solar cells deposited on untextured (flat) and randomly textured substrates. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Self-Assembled Octadecyltrimethoxysilane Monolayers Enabling Selective-Area Atomic Layer Deposition of Iridium

CHEMICAL VAPOR DEPOSITION, Issue 7 2006
E. Färm
A preparation method for octadecyltrimethoxysilane (ODS) self-assembled monolayers (SAMs) that enables the selective-area ALD of iridium is studied using an ALD process for iridium at 225,°C. ODS SAMs were prepared from the gas phase by two preparation methods: either with exposure to ODS only, or with alternate exposures to ODS and water. SAMs were patterned with a lift-off process using aluminium as a mask layer. [source]