Pattern transfer and photoluminescence damage assessment of deep-submicrometer features etched by photon-induced cryoetching

We present a study of pattern-transfer and etch-induced damage in photon-induced cryoetching. Features with effective radii as small as 100 nm have been formed in both bulk and layered GaAs/AlGaAs materials. A measurement of the photoluminescence of etch-defined deep- submicrometer structures material suggests that this form of etching results in minimal process-induced damage. Modeling of the luminescence vs feature size for these features shows that the luminescence is limited only by carrier diffusion and non-radiative surface recombination.     

Surface-catalyzed photochemical reactions of physisorbed molecules

The rate of laser photochemical reactions on surfaces can be enhanced over their gas-phase values by the interplay of a number of surface phenomena. These effects include simple increases in molecular density due to physisorption, spectral shifts in the adsorbed phase, and enhancement in the optical electric field due to surface contouring.     

Zur Differentiation des bestimmten Integrales nach einem Parameter

Ohne ZusammenfassungAuszug aus einem Schreiben an Herrn O. Stolz.     

Product type bounds on the approximation of values ofE andG functions

This paper obtains effective lower bounds on the absolute values of linear forms, over the integers, in power products of values of certain SiegelE-functions or SiegelG-functions. The bounds obtained are in terms of the product of the absolute values of the coefficients. ForE-functions the bound obtained is a best possible result, up to an arbitrarily small positive epsilon. ForG-functions the result is asymptotically best in the following sense: for each epsilon larger than zero there exists an integerN such that ifz, the point of evaluation, equalsM ^–1 whereM is an integer with absolute value larger thanN, then the bound obtained is within epsilon of a best possible bound. (From the proof it is clear thatz need not be the inverse of an integer. What is necessary that the absolute value of its numerator must be much smaller than the absolute value of its denominator.)Results obtained recently by D. V. andG. V. Chudnovsky bounding the absolute values of similar forms give bounds in terms of the maximum of the absolute values of the coefficients; such lower bounds can be much smaller.Dedicated to Professor E. Hlawka on the occasion of his seventieth birthday     

Characteristics of copper HyBrID-type lasers which use HCl reactive gas

We have investigated the output behaviour of a low temperature HyBrID-type copper laser operating with a flowing Ne–HCl reactive gas mixture. 15.5 W of average power was observed from a 19 mm bore device at 23 kHz PRF corresponding to a specific output power of 78 mW/cm3. The output power was 20–30% lower than that of the same device operating with an Ne–HBr mixture; however, it markedly exceeds the output of similar sized elemental copper vapour lasers (with or without hydrogen additive). This revised version was published online in June 2006 with corrections to the Cover Date.     

Nearly perfect systems and effective generalizations of Shidlovski's Theorem

An effective proof of Shidlovski's Theorem is presented. The proof utilizes partial differential operators. A number of generalizations of Shidlovski's Theorem are proven, including results about approximation at more than one point. Additionally, partial differential equations are considered. The new methods give a particularly direct proof of Shidlovski's Theorem.     

Monte carlo methods and lattice discontinuities

The choice of the Monte Carlo method for the theoretical study of lattice discontinuities, such as surfaces, grain boundaries and dislocations is justified. A brief, non-rigorous discussion of the basic statistical mechanics required to develop the Monte Carlo method is given. Current work in the theoretical study of interfacial systems in solids is reviewed and problems to which the Monte Carlo method might be applied are suggested.     

The simultaneous diophantine approximation of values of functions satisfying certain n variable q-difference equations

In a previous paper lower bounds were obtained on the simultaneous diophantine approximation of values of certain functions which satisfy linear q-difference equations. In the present paper these results are generalized from n = 1 to n > 1 variables. In order to better see what some of these solutions “look like” the algebraic properties of certain classes of functions are investigated, particularly with regard to a type of multiplication which is analogous to the convolution product. At the end of the paper such algebraic results are also obtained for the case n = 1.