Abstract: An improved resistive ribbon for thermal transfer priting in which a coating is located on the resistive layer in order to reduce contact resistance between the ribbon and printhead, thereby reducing undesirable heating at the contact region between the ribbon and printhead. The coating is comprised of compositions selected from the group consisting of Cr-N, Sn-SnO, ITO, AlN and Al-Al.sub.2 O.sub.3, where the resistivity of the coating is significantly less than the resistivity of the resistive layer of the ribbon. Further, the sheet resistivity of the coating is greater than the sheet resistivity of the resistive layer. The rest of the resistive ribbon can be comprised of any combination of the usually employed layers, such as a current return layer, a release layer for facilitating the transfer of ink from the ribbon to a carrier, and the ink layer itself.

Abstract: An improved resistive ribbon for thermal transfer printing is provided, where the ribbon includes a resistive layer, a metal current-return layer, a fusible ink layer, and an electric interface layer located between the resistive layer and the metal layer. The electrical interface layer is sufficiently thin so as not to impair the required mechanical properties of the ribbon (such as flexibility, stability, durability, etc.), and has as its primary function the enhancement of the electrical porperties of the ribbon. Specifically, interface resistance and/or knee voltage of the current-voltage characteristics of the ribbon are enhanced by the electrical interface layer.Preferred compositions of the interface layer include alkylalkoxy silanes of a specific formula, and especially nonsymmetrical compounds of that formula.

Abstract: A resistive ribbon printing technique is described in which the ribbon includes a resistive layer comprised of a metal-wide bandgap insulator combination. The ribbon also includes a support layer, where the support function can be provided by the resistive layer, and a fusible ink layer. Electrical current through the resistive layer produces heat which locally melts the ink for transfer to an adjacent receiving medium. The wide bandgap insulator of the resistive layer must have a bandgap of at least three volts. Many different metals and insulators can be used, where the relative amounts of metal and insulator are chosen to provide a desired resistivity for any type of resistive ribbon printing application.

Abstract: Chemical heat amplification is provided in thermal transfer printing, wherein some of the heat necessary for melting and transferring ink from a solid fusible layer in a ribbon to a receiving medium is provided by an exothermic reaction. This chemical reaction is due to an exothermic material that is located in the ink layer, or in another layer of the ink bearing ribbon. The exothermic reaction reduces the amount of the input power which must be applied either electrically or with electromagnetic waves. Examples of suitable exothermic materials are those which will provide heat within the operative temperature range of the ink, and include nonaromatic azo compounds, peroxides, and strained valence compounds, such as monomers, dimers, trimers, of the type which change their chemical bonding when they decompose to either a valence isomer or break into a number of molecular species.

Abstract: A resistive ribbon for thermal transfer printing comprising a support layer bearing a fusible ink composition and a thin aluminum layer upon which is deposited a resistive layer of non-stoichiometric metal silicide is disclosed. Also disclosed are appropriate power sources for using the resistive ribbon, as well as methods for non-impact printing employing the disclosed ribbon.

Abstract: The invention is directed to a novel method for detecting surface damage to polished silicon wafers. For very fine defects and scratches an oxidation step is used. The oxide is removed and the wafer is treated in an etch solution containing pyrocatechol, ethylene diamine and water. The defects are detectable by the naked eye.

Abstract: Multicolor light emitting diode arrays can be made using a binary semiconductor substrate on which is grown a graded epitaxial region of an AB.sub.1-x C.sub.x semiconductor. Diodes emitting various light colors can selectively be formed in different regions of the gradient by etching away a portion of the graded region. Arrays of colored light emitting diodes can be made by the techniques of diffusion and selective etching of the graded material.

Abstract: Monolithic light emitting diode arrays may be fabricated by using a two layer binary semiconductor substrate wafer providing a gradient of ingredient concentration in one portion of the wafer and forming p-n junctions to a desired depth in the graded concentrated wafer and selectively removing portions of the opposite side of the wafer adjacent to said p-n junctions in order to permit light of varying colors to escape and to provide optical isolation. Metallurgical pads are provided to each of the p-n junctions for solder reflow type connections.

Abstract: Monolithic light emitting diode arrays may be fabricated by using a two layer binary semiconductor substrate wafer providing a gradient of ingredient concentration in one portion of the wafer and forming p-n junctions to a desired depth in the graded concentrated wafer and selectively removing portions of the opposite sides of the wafer adjacent to said p-n junctions in order to permit light of varying colors to escape and to provide optical isolation. Metallurgical pads are provided to each of the p-n junctions for solder reflow type connections.

Abstract: Multicolor light emitting diode arrays can be made using a binary semiconductor substrate on which is grown a graded epitaxial region of an AB.sub.1-x C.sub.x semiconductor. Diodes emitting various light colors can selectively be formed in different regions of the gradient by etching away a portion of the graded region. Arrays of colored light emitting diodes can be made by the techniques of diffusion and selective etching of the graded material.