Abstract: A reflector stack or acoustic mirror arrangement for an acoustic device is described which may attain the highest possible impedance mismatch between alternating higher and lower impedance reflecting layers of the stack, so as to maximize bandwidth. The arrangement may also reduce manufacturing costs by requiring fewer layers for the device, as compared to conventional acoustic mirrors. The thinner reflecting stack is accordingly fabricated in reduced time to lower cost, by incorporating materials providing a larger acoustic impedance mismatch than those currently obtainable. The bandwidth of the resulting acoustic resonator device may be widened, particularly when a low density material such as aerogel, CVD SiO2 and/or sputter deposited SiO2 is applied as topmost layer in the reflector stack/acoustic mirror arrangement of the device.

Abstract: Disclosed are a method of making GaAs-based enhancement-type MOS-FETs, and articles (e.g., GaAs-based ICs) that comprise such a MOS-FET. The MOS-FETs are planar devices, without etched recess or epitaxial re-growth, with gate oxide that is primarily Ga2O3, and with low midgap interface state density (e.g., at most 1×1011 cm−2 eV−1 at 20° C.). The method involves ion implantation, implant activation in an As-containing atmosphere, surface reconstruction, and in situ deposition of the gate oxide. In preferred embodiments, no processing step subsequent to gate oxide formation is carried out above 300° C. in air, or above about 700° C. in UHV. The method makes possible fabrication of planar enhancement-type MOS-FETs having excellent characteristics, and also makes possible fabrication of complementary MOS-FETs, as well as ICs comprising MOS-FETs and MES-FETs.

Abstract: Disclosed are articles that comprise an oxide layer on a GaAs-based semiconductor body, with metal layers on the oxide and the body facilitating application of an electric field across the oxide layer. The interface between the oxide and the semiconductor body is of device quality. Contrary to teachings of the prior art, the oxide is not essentially pure Ga.sub.2 O.sub.3, but instead has composition Ga.sub.x A.sub.y O.sub.z, where A is an electropositive stabilizer element adapted for stabilizing Ga in the 3+ oxidation state. Furthermore, x.gtoreq.0, z is selected to satisfy the requirement that both Ga and A is substantially fully oxidized and y/(x+y) is greater than 0.1. Stabilizer element A typically is selected from Sc, Y, the rare earth elements and the alkaline earth elements. Articles according to the invention exemplarily comprise a planar enchancement mode MOS-FET with inversion channel. A method of making articles as described above is also disclosed.

Abstract: Carbonaceous materials based on the fullerene molecules have been developed which allow for superconductivity. The fullerene materials are soluble in common solvents.

Abstract: Nonaqueous, rechargeable batteries are described which employ a conventional negative electrode and a positive electrode with a new and unique active material. Such batteries are advantageous because of the high capacity per unit weight and per unit volume exhibited by the positive electrode and the extensive rechargeability of these batteries.