Shadow mask

About: Shadow mask is a research topic. Over the lifetime, 3229 publications have been published within this topic receiving 17967 citations.

Network single-walled carbon nanotube-field effect transistors (SWNT-FETs) with increased Schottky contact area for highly sensitive biosensor applications.

Abstract: Highly sensitive single-walled carbon nanotube-field effect transistor (SWNT-FET) devices, which detect protein adsorptions and specific protein−protein interactions at 1 pM concentrations, have been achieved. The detection limit has been improved 104-fold compared to the devices fabricated by photolithography. The substantially increased sensitivity is mainly due to the increased Schottky contact area which accommodates relatively more numbers of proteins even at very low concentration. The augmented number of proteins adsorbed on a device induces instant modulation of the work function of metal contact electrodes, which eventually changes the conductance of the device. Such devices have been attained by addressing metal electrodes on network-type SWNTs using a shadow mask on a tilted angle sample stage. The shadow mask allows metals to penetrate underneath the mask efficiently, therefore forming a thin and wide Schottky contact area on SWNT channels.

Solution‐Processed Full‐Color Polymer Organic Light‐Emitting Diode Displays Fabricated by Direct Photolithography

Abstract: The first full-color polymer organic light-emitting diode (OLED) display is reported, fabricated by a direct photolithography process, that is, a process that allows direct structuring of the electroluminescent layer of the OLED by exposure to UV light. The required photosensitivity is introduced by attaching oxetane side groups to the backbone of red-, green-, and blue-light-emitting polymers. This allows for the use of photolithography to selectively crosslink thin films of these polymers. Hence the solution-based process requires neither an additional etching step, as is the case for conventional photoresist lithography, nor does it rely on the use of prestructured substrates, which are required if ink-jet printing is used to pixilate the emissive layer. The process allows for low-cost display fabrication without sacrificing resolution: Structures with features in the range of 2 μm are obtained by patterning the emitting polymers via UV illumination through an ultrafine shadow mask. Compared to state-of-the-art fluorescent OLEDs, the display prototype (pixel size 200 μm × 600 μm) presented here shows very good efficiency as well as good color saturation for all three colors. The application in solid-state lighting is also possible: Pure white light [Commision Internationale de l'Eclairage (CIE) values of 0.33, 0.33 and color rendering index (CRI) of 76] is obtained at an efficiency of 5 cd A–1 by mixing the three colors in the appropriate ratio. For further enhancement of the device efficiency, an additional hole-transport layer (HTL), which is also photo-crosslinkable and therefore suitable to fabricate multilayer devices from solution, is embedded between the anode and the electroluminescent layer.

A full color active matrix organic electroluminescent display panel having an integrated shadow mask

Abstract: A full-color active matrix organic light-emitting color display panel is disclosed which has an integrated shadow mask structure for patterning arrays of color subpixels. The in-situ shadow mask structure is prepatterned on the display substrate by conventional photolithography, and provides a simple, self-alignment feature for successive deposition of color organic electroluminescent (EL) media on designated color subpixel areas. The pillar structure of the shadow mask are particularly effective in the fabrication of high-resolution full-color organic light-emitting diode displays having either color conversion layers or individual red, green, and blue emissive layers.

Large-area uniform electron source

Abstract: A large-area electron source (22) which can operate continuously, stably, and indefinitely in a poor vacuum (20) environment. The source includes a glow discharge cathode, appropriately positioned with respect to a target anode (30) and a fine-mesh grid (26) spaced from the cathode (22) by a distance less than the mean free path length of electrons leaving the cathode (22), the grid (26) being electrically biased to control the electron beam current over a wide range with only small grid voltage changes. An accelerating voltage (29) applied to the cathode (22) can be varied continuously from as low as a few hundred volts to 30 KeV or greater and the source will continue to operate satisfactorily. Further, the grid (26) is made of a fine mesh wire of sufficiently small dimensions as to not be resolvable in the target plane (30). A further refinement of the device utilizes scanning coils (34) to achieve additional uniformity of the incident beam at the target plane (30). The basic apparatus of the invention can be combined with other features, for use in shadow mask lithography, resist sensitivity measurement, lift off processing, and resist curing.

Parallel nanodevice fabrication using a combination of shadow mask and scanning probe methods

Abstract: We describe a resistless proximal probe-based lithography technique, which enables the direct patterning of complex and submicron-sized structures of various materials. The method is based on a combination of scanning probe microscopy and the shadow masking technique, whereby structures are locally deposited through pinhole-like apertures situated in the proximity of a cantilever tip. Predefined excursions of the sample lead to the direct fabrication of arbitrary structures on the surface. Complex patterns such as rings and intersecting lines with linewidths well below 0.1 μm are presented.