Metal Transfer Printing and Its Application in Organic Field‐Effect Transistor Fabrication

Abstract

is concerned, the present finding bears essential implications for applying the superplastic forming of ceramics into a costeffective industrial production of complex shaped silicon nitride-based components, and for production of other polycrystalline materials that are sintered to full density via a liquid-phase sintering process. ExperimentalThe starting powders were Si 3 N 4 (Ube, SN-E10), AlN (HC Starck, Grade C), Al 2 O 3 , Y 2 O 3 , and Yb 2 O 3 (Johnson Matthey Chemicals Ltd.). When calculating the compositions, corrections were made for the small amounts of oxygen present in the Si 3 N 4 and AlN precursor powders. The starting materials, in batches of 50 g, were ball milled in water-free propanol for 24 h, using sialon milling media. The dried powders were consolidated in vacuum in an SPS apparatus, Dr. Sinter 2050 (Sumitomo Coal Mining Co. Ltd., Japan). The powder precursors were loaded in cylindrical carbon dies with an inner diameter of 12 mm. The samples were heated via a pulsed direct current that passed through the pressure die, i.e., the pressure die also acted as a heating source. The temperature was automatically raised to 600 C over a period of 3 min, and from this point on it was monitored and regulated by an optical pyrometer focused on the surface of the die. A heating rate of 200 C min ±1 was used, and a uniaxal pressure of 50 MPa was applied from the start to the end of the sintering cycle. The set-up allowed a cooling rate of~400 C min ±1 in the temperature range 1800±1000 C.The compressive deformation tests were carried out both in the SPS apparatus and in a conventional HP chamber heated by surrounding graphite heating elements. The fully densified cylindrical samples, with a diameter of 12 mm and a height of~6 mm, were loaded in a graphite die with an inner diameter of 20 mm, and deformed by applying a compressive stress through the oppositely moving graphite punches.The crystalline phase assemblies present in the sintered ceramics were determined from Guinier±Hägg X-ray powder diffraction patterns, using monochromatic Cu Ka radiation and Si as an internal standard. Both fractured and polished surfaces of the samples were examined in a scanning electron microscope (Jeol JSM 880) equipped with an energy-dispersive spectrometer (EDS, LINK ISIS). In order to obtain the best contrast between different phases, the microscopy images were recorded in back-scattered electron mode, where the a-sialon and Yb/Y-enriched intergranular glassy phases show medium gray and bright contrasts, respectively, whereas b-sialon, if present, appears with in dark (black) contrast. The amounts of intergranular glassy phase were evaluated with an image-analyzing package supplied with the LINK ISIS system. The contrast difference between the a/b-sialon grains and the Yb/Y-containing glassy phase was used to estimate the phase content in vol.-%, which was assumed valid for the whole sample volume. The estimated minimum and maximum amounts of glassy phase gave an error of ± 1 %.

Gradient biomaterials and their influences on cell migration

“…Recently, a series of technologies have been developed based on microcontact printing (mCP), such as decal transfer microlithography [96], nanotransfer printing [94] and metal transfer printing [97,98]. Jeon et al [99] found that the surface coverage of octadecyltrichlorosilane (OTS) was augmented by prolongation of contact time.…”

Nanoscale Patterning and Electronics on Flexible Substrate by Direct Nanoimprinting of Metallic Nanoparticles

“…In order to address the current problems of microfabrication on flexible substrate, many alternative approaches to conventional photolithography-based process have been introduced by a number of researchers. These include microcontact printing (lCP) combined with metal etching, [10] electroless plating, [11] electropolymerization, [12] and direct metal layer transfer [13] for the microscale metal patterning on flexible substrates. Stencil lithography [14] was mainly applied for dielectric layer patterning on polymer substrates for the formation of electrical capacitors [15,16] due to its limited resolution.…”

Patterning of Semiconductor Nanoparticles via Microcontact Printing

“…[ 41] Here we found that metal transference could also be initiated at room temperature under pressure with a slightly longer printing time. Forty-nm Au was thermally evaporated on structured stamps.…”