Abstract: The present invention relates to small sample spots for MALDI targets and methods for producing the same. The sample spots are composed of a layer of matrix material and a layer of analyte. In some instances, the samples spots have diameters of no more than 50 micrometers or even smaller. The sample spots are deposited onto a MALDI target substrate using ultrasonic deposition from a nozzle.

Abstract: Devices and methods for depositing fluids on substrates in patterns of spots, lines, or other features use a nozzle, which is preferably configured similarly to a micropipette, having a piezoelectric crystal or other ultrasonic actuator coupled to one of its sides. The nozzle may be charged via capillary action by dipping it into a well containing the fluid to be deposited, and may then be positioned over a desired area of a substrate, at which point activation of the ultrasonic actuator at ultrasonic frequencies will eject the fluid onto the substrate. The needle may subsequently be dipped into a well of rinsing fluid for cleaning. Spots or lines on the order of 5 micrometers width may be generated, making the invention particularly suitable for use in biological applications such as microarray production and in microelectronics applications such as the printing of organic circuitry.

Abstract: A suspended semiconductor film is anchored to a substrate at at least two opposed anchor positions, and film segments are deposited on the semiconductor film adjacent to one or more of the anchor positions to apply either tensile or compressive stress to the semiconductor film between the film segments. A crystalline silicon film may be anchored to the substrate and have tensile stress applied thereto to reduce the lattice mismatch between the silicon and a silicon-germanium layer deposited onto the silicon film. By controlling the level of stress in the silicon film, the size, density and distribution of quantum dots formed in a high germanium content silicon-germanium film deposited on the silicon film can be controlled.

Abstract: A suspended semiconductor film is anchored to a substrate at at least two opposed anchor positions, and film segments are deposited on the semiconductor film adjacent to one or more of the anchor positions to apply either tensile or compressive stress to the semiconductor film between the film segments. A crystalline silicon film may be anchored to the substrate and have tensile stress applied thereto to reduce the lattice mismatch between the silicon and a silicon-germanium layer deposited onto the silicon film. By controlling the level of stress in the silicon film, the size, density and distribution of quantum dots formed in a high germanium content silicon-germanium film deposited on the silicon film can be controlled.

Abstract: Devices and methods for depositing fluids on substrates in patterns of spots, lines, or other features use a nozzle, which is preferably configured similarly to a micropipette, having a piezoelectric crystal or other ultrasonic actuator coupled to one of its sides. The nozzle may be charged via capillary action by dipping it into a well containing the fluid to be deposited, and may then be positioned over a desired area of a substrate, at which point activation of the ultrasonic actuator at ultrasonic frequencies will eject the fluid onto the substrate. The needle may subsequently be dipped into a well of rinsing fluid for cleaning. Spots or lines on the order of 5 micrometers width may be generated, making the invention particularly suitable for use in biological applications such as microarray production and in microelectronics applications such as the printing of organic circuitry.

Abstract: A membrane having a stable low-contact angle that is used as a template in forming biological microarrays is provided. The membrane is formed of a polymeric material that has been surface modified by a first plasma treatment and subsequently by a second plasma treatment. The surface modification accomplished by the first plasma treatment results in a significant reduction in the contact angle for the membrane, causing the membrane to become hydrophilic, and the surface modification by the second membrane treatment permanently stabilizes the reduction in the contact angle produced by the first plasma treatment. The resulting membrane allows a solution containing a biological material to wet the surface of the membrane such that the membrane can quickly and easily form a biological microarray on substrate in which the features of the array are distinctly formed on the substrate.

Abstract: A suspended semiconductor film is anchored to a substrate at at least two opposed anchor positions, and film segments are deposited on the semiconductor film adjacent to one or more of the anchor positions to apply either tensile or compressive stress to the semiconductor film between the film segments. A crystalline silicon film may be anchored to the substrate and have tensile stress applied thereto to reduce the lattice mismatch between the silicon and a silicon-germanium layer deposited onto the silicon film. By controlling the level of stress in the silicon film, the size, density and distribution of quantum dots formed in a high germanium content silicon-germanium film deposited on the silicon film can be controlled.

Abstract: Semiconductor dot devices include a multiple layer semiconductor structure having a substrate, a back gate electrode layer, a quantum well layer, a tunnel barrier layer between the quantum well layer and the back gate, and a barrier layer above the quantum well layer. Multiple electrode gates are formed on the multi-layer semiconductor with the gates spaced from each other by a region beneath which quantum dots may be defined. Appropriate voltages applied to the electrodes allow the development and appropriate positioning of the quantum dots, allowing a large number of quantum dots be formed in a series with appropriate coupling between the dots.

Abstract: Semiconductor dot devices include a multiple layer semiconductor structure having a substrate, a back gate electrode layer, a quantum well layer, a tunnel barrier layer between the quantum well layer and the back gate, and a barrier layer above the quantum well layer. Multiple electrode gates are formed on the multi-layer semiconductor with the gates spaced from each other by a region beneath which quantum dots may be defined. Appropriate voltages applied to the electrodes allow the development and appropriate positioning of the quantum dots, allowing a large number of quantum dots be formed in a series with appropriate coupling between the dots.

Abstract: A piezoelectric positioner is accurately controlled to reduce the settling time of the positioner in response to a commanded change in position using velocity state feedback control. The velocity state feedback control uses an estimated velocity of the piezoelectric positioner generated by a velocity observer to provide active damping. The velocity observer has as inputs the same control signal which is provided to the piezoelectric positioner itself and the actual measured position of the positioner, and produces as an output the estimated velocity of the positioner. The velocity observer includes a model of the piezoelectric positioner's response to the control signal. The model includes estimates of physical parameters of the positioner including the physical mass, physical damping, and physical stiffness of the positioner.

Abstract: A field emission electron gun (10) is disclosed which has an extraction electrode, composed of one or more sharply pointed electrode tips (17) in close proximity to a field emission cathode tip (11), such that a relatively low voltage between the cathode tip (11) and the extraction electrode tips (17), in the range of 100 to 2000 volts, will cause field emission of electrons from the cathode tip due to the extremely high localized electric field at the cathode tip. The electrons in the beam extracted from the cathode (11) are at a relatively low kinetic energy, particularly adapting the beam for use in such applications as low energy electron microscopy and low energy electron diffraction. For such applications, the extracted beam is generally passed through a limiting aperture member (21), electrostatic lenses (24, 25), and a deflection coil (26) when scanning of the target (27) is desired.