Alternating Current Electroluminescence for Human-Interactive Sensing Displays.

The development of stimuli-interactive displays based on alternating current (AC)-driven electroluminescence (EL) is of great interest, owing to their simple device architectures suitable for wearable applications requiring resilient mechanical flexibility and stretchability. AC-EL displays can serve as emerging platforms for various human-interactive sensing displays (HISDs) where human information is electrically detected and directly visualized using EL, promoting the development of the interaction of human-machine technologies. This review provides a holistic overview of the latest developments in AC-EL displays with an emphasis on their applications for HISDs. AC-EL displays based on exciton recombination or impact excitations of hot electrons are classified into four representative groups depending upon their device architecture: 1) displays without insulating layers, 2) displays with single insulating layers, 3) displays with double insulating layers, and 4) displays with EL materials embedded in an insulating matrix. State-of-the-art AC HISDs are discussed. Furthermore, emerging stimuli-interactive AC-EL displays are described, followed by a discussion of scientific and engineering challenges and perspectives for future stimuli-interactive AC-EL displays serving as photo-electronic human-machine interfaces.

Dynamics of the Dissociating Uracil Anion Following Resonant Electron Attachment.

We report a combined experimental and theoretical investigation of dissociative electron attachment (DEA) to the nucleobase uracil. Using ion momentum imaging experiments employing a DEA reaction microscope we have measured 3-dimensional momentum distributions of specific anionic fragments following DEA to uracil by 6 eV electrons. From the measured anion fragment kinetic energy we determine the possible dissociation pathways and the total kinetic energy release. We employ electronic structure and electron scattering calculations to determine the probability for electron attachment in the molecular frame. Combining these calculations with the imaging measurements, we reveal several key features of the coupled electronic and nuclear dynamics of DEA.

Activation of Metal-Organic Precursors by Electron Bombardment in the Gas Phase for Enhanced Deposition of Solid Films.

The incorporation of gas-phase electron-impact ionization and activation of metal-organic compounds into atomic layer deposition (ALD) processes is reported as a way to enhance film growth with stable precursors. Specifically, it is shown here that gas-phase activation of methylcyclopentadienylmanganese tricarbonyl, MeCpMn(CO)3, which was accomplished by using a typical nude ion gauge employed in many ultrahigh-vacuum (UHV) studies, enhances its dissociative adsorption on silicon surfaces, affording the design of ALD cycles with more extensive Mn deposition and at lower temperatures. Significantly higher Mn uptakes were demonstrated by X-ray photoelectron spectroscopy (XPS) on both silicon dioxide films and on Si(100) wafers Ar(+)-sputtered to remove their native oxide layer. The effectiveness of this electron-impact activation approach in ALD is explained in terms of the cracking patterns seen in mass spectrometry for the metal-organic precursor used.

Excitation of O2 1Δg by Electron Impact.

The total and differential cross sections as a function of energy were calculated for electron impact excitation of the O2 1Δ g state from the ground 3 ∑ g ¯ state. The Ochkur-Rudge approximation was used for the exchange amplitude, which was calculated using Hartree-Fock. wave functions with a Gaussian basis. There is good agreement with the experimental total cross section except near threshold.

Electron Impact Excitation of Hydrogen Lyman- α Radiation.

An experimental investigation of electron impact excitation of the 2p state of atomic hydrogen is described. A beam of electrons was passed through a chopped beam of hydrogen atoms in a high vacuum apparatus. The modulated flux of Lyman-α photons emitted in the radiative decay of the 2p state was taken as a measurement of the excitation probability resulting from direct excitation plus indirect excitation resulting from cascading. The region surrounding the intersection of the two beams was electrically and magnetically shielded to prevent quenching of metastable 2s atoms and thereby to ensure that the observed Lyman-α flux resulted from decay of the short-lived 2p state. The experimental results are consistent with those obtained by Fite, Stebbings, and Brackmann [1959], and confirm the existence of a large discrepancy between theoretical and experimental results in the electron energy range below 50 eV.