Coulomb blockade in a Si channel gated by an Al single-electron transistor

We incorporate an Al-AlO_x-Al single-electron transistor as the gate of a narrow (~100 nm) metal-oxide-semiconductor field-effect transistor (MOSFET). Near the MOSFET channel conductance threshold, we observe oscillations in the conductance associated with Coulomb blockade in the channel, revealing the formation of a Si single-electron transistor. Abrupt steps present in sweeps of the Al transistor conductance versus gate voltage are correlated with single-electron charging events in the Si transistor, and vice versa. Analysis of these correlations using a simple electrostatic model demonstrates that the two single-electron transistor islands are closely aligned, with an inter-island capacitance approximately equal to 1/3 of the total capacitance of the Si transistor island, indicating that the Si transistor is strongly coupled to the Al transistor.Comment: 3 pages, 4 figures, 1 table; typos corrected, minor clarifications added; published in AP

X-ray and low energy gamma-ray observations of the 16 February 1984 solar flare

The February 16, 1984 (0900 UT) solar flare was very energetic and produced a variety of emissions. The X-ray and gamma ray continuum measurement, made aboard the International Cometary Explorer (ICE) and the Pioneer Venus Orbiter (PVO), are briefly described

InN dielectric function from the midinfrared to the visible range

The dispersion of the dielectric function for wurtzite InN is analytically evaluated in the region near the fundamental energy gap. The real part of the dielectric function has a logarithmic singularity at the absorption edge. This results in the large contribution into the optical dielectric constant. For samples with degenerate carriers, the real part of the dielectric function is divergent at the absorption edge. The divergence is smeared with temperatures or relaxation rate. The imaginary part of the dielectric function has a plateau far away from the absorption onset.Comment: 5 pages, 2 figure

High mobility two-dimensional electron system on hydrogen-passivated silicon(111) surfaces

We have fabricated and characterized a field-effect transistor in which an electric field is applied through an encapsulated vacuum cavity and induces a two-dimensional electron system on a hydrogen-passivated Si(111) surface. This vacuum cavity preserves the ambient sensitive surface and is created via room temperature contact bonding of two Si substrates. Hall measurements are made on the H-Si(111) surface prepared in aqueous ammonium fluoride solution. We obtain electron densities up to $6.5 \times 10^{11}$ cm$^{-2}$ and peak mobilities of $\sim 8000$ cm$^{2}$/V s at 4.2 K.Comment: to appear in Applied Physics Letter