Molecular beam epitaxial regrowth of InAs/AiSb/GaSb heterostructures on patterned substrates

The molecular beam epitaxial growth of InAs/AISb/GaSb heterostructures on GaSb epilayers patterned by dry etching is investigated. Faceted growth occurs at pattern edges, depending on the adatom species, crystallographic planes and growth parameters. The morphology of the overgrown structure is determined by (111), (110), and (100) Planes near the edges of the patterned stripes, oriented in the [011], [001 ], or [0 11] direction. During the regrowth of InAs, additional (311)A planes are formed at the edges for stripe orientations in the [0 11] direction. Utilizing the faceted growth behavior at pattern edges, resonant interband tunneling diodes with a room temperature peak-to-valley current ratio of 13 have been fabricated on patterned substrates. The results indicate that this approach has the potential of realizing advanced devices with higher complexity.     

Zur Struktur endlicher auflösbarer Gruppen mit mindestens drei Untergruppen von paarweise teilerfremden Indizes

Ohne Zusammenfassung     

Static random access memories based on resonant interband tunnelingdiodes in the InAs/GaSb/AlSb material system

We have fabricated SRAM's based on resonant interband tunneling diodes in the InAs/AlSb/GaSb material system. The bistability and the switching principles are demonstrated. Numerical simulations of the memory characteristics of the SRAM cell are performed and used for comparing with experiments. Several key issues involving the applications of the device are also discussed     

Construction of new symmetric designs with parameters (66,26,10)

It is known that there exists only one (Tran van Trung's) design for (66,26,10) up to now. In this article we consider designs for (66,26,10) with the Frobenius group F₃₉ and we prove that there exist (up to isomorphism) exactly 18 such designs. © 1995 John Wiley & Sons, Inc. We characterize the proper t-wise balanced designs t?(v,K,1) for t ? 3, λ = 1 and v ? 16 with at least two block sizes. While we do not examine extensions of S(3,4,16)'s, we do determine all other possible extensions of S(3,K,v)'s for v ? 16. One very interesting extension is an S(4, {5,6}, 17) design. © 1995 John Wiley & Sons, Inc.     

Transportable He-Ne/CH4 optical frequency standard andabsolute measurements of its frequency

A new version of a transportable double-mode He-Ne/CH₄ laser (3.39 μm) stabilized on the resolved hyperfine structure (HFS) of the F₂/sup (2/) methane line was designed at Lebedev Physical Institute. Absolute frequency measurements of the laser were made at the radio-optical frequency chain of Physikalisch-Technische Bundesanstalt, Braunschweig, Germany (PTB). Various reasons for frequency shifts were investigated. Computer processing of the observed line shape was used to calculate the nonperturbed frequency of the central component of HFS     

FM-noise measurements on an optically pumped FIR laser

We report the noise measurements performed on a synthesized signal at 761 GHz starting from a 5 MHz quartz oscillator, as well as the investigation of the frequency noise of an optically pumped FIR laser and the possible origin of this noise. Bandwidth requirements for phase-locking an FIR laser are obtained.     

Hyperfine fields and chemical order in Fe-Ge

Films of Fe_0.79Ge_0.21 were synthesized by ion beam sputtering, and were annealed at temperatures from 150 to 500 °C. The as-prepared materials comprised chemically disordered bcc crystallites, but short-range and long-range D0₃ chemical order developed upon annealing. The⁵⁷Fe hyperfine magnetic field distribution can be understood approximately with a model of magnetic response, so the hyperfine magnetic field distribution can be used to follow the changes in chemical short-range ordering. Large local isomer shifts were observed at⁵⁷Fe atoms near Ge atoms.     

Proper S(t,K,v)'s for t ≥ 3,v ≤ 16, |K| > 1 and Their Extensions

We characterize the proper t-wise balanced designs t-(v,K,1) for t ≥ 3, λ = 1 and v ≤ 16 with at least two block sizes. While we do not examine extensions of S(3,4,16)'s, we do determine all other possible extensions of S(3,K,v)'s for v ≤ 16. One very interesting extension is an S(4, {5,6}, 17) design.©1995 John Wiley & Sons, Inc.