Eugene E. Haller

Black Ge Based on Crystalline/Amorphous Core/Shell Nanoneedle Arrays

Direct growth of black Ge on low-temperature substrates, including plastics and rubber is reported. The material is based on highly dense, crystalline/amorphous core/shell Ge nanoneedle arrays with ultrasharp tips ( approximately 4 nm) enabled by the Ni catalyzed vapor-solid-solid growth process. Ge nanoneedle arrays exhibit remarkable optical properties. Specifically, minimal optical reflectance (<1%) is observed, even for high angles of incidence ( approximately 75 degrees ) and for relatively short nanoneedle lengths ( approximately 1 mum). Furthermore, the material exhibits high optical absorption efficiency with an effective band gap of approximately 1 eV. The reported black Ge could potentially have important practical implications for efficient photovoltaic and photodetector applications on nonconventional substrates.

Deep Level Transient Spectroscopy of High-Purity Germanium Diodes/Detectors

Deep Level Transient Spectroscopy (DLTS) has been applied for the first time to high-purity germanium p-i-n diodes. Using the correlator technique, a large number of peaks due to acceptor levels in the forbidden band have been observed. The levels due to substitutional copper, to copper-hydrogen complexes and to divacancy-hydrogen defects have been positively identified. Several unknown levels have been discovered. The results obtained with DLTS are in excellent agreement with results from Hall-effect measurements. DLTS is the perfect tool to follow the creation and annealing of radiation defects.

Effect of pulse error accumulation on dynamical decoupling of the electron spins of phosphorus donors in silicon

Dynamical decoupling (DD) is an efficient tool for preserving quantum coherence in solid-state spin systems. However, the imperfections of real pulses can ruin the performance of long DD sequences. We investigate the accumulation and compensation of different pulse errors in DD using the electron spins of phosphorus donors in silicon as a test system. We study periodic DD sequences (PDD) based on spin rotations about two perpendicular axes, and their concatenated and symmetrized versions. We show that pulse errors may quickly destroy some spin states, but maintain other states with high fidelity over long times. Pulse sequences based on spin rotations about

Far-Infrared Magneto-Absorption of Bound Excitons in Beryllium Doped Germanium

x

Reduced thermal conductivity of isotopically modulated silicon multilayer structures

and

Results from a search for the 0 neutrino beta beta-decay of Te-130

y

Status and problems of semiconductor detectors

axes outperform those based on

A Two-Dimensional Position Sensitive Si(Li) Detector

x

Doping dependence of self-diffusion in germanium and the charge states of vacancies

and

Annealing Characteristics Of Low Temperature Grown GaAs:Be

z