MIT News July 21, 2022 Among the ultrahigh–thermal conductivity materials, cubic boron arsenide (c-BAs) is predicted to exhibit simultaneously high electron and hole mobilities of >1000 centimeters squared per volt per second. Using the optical transient grating technique, a team of researchers in the US (MIT, University of Houston, UT Austin, Boston College) experimentally measured thermal conductivity of 1200 watts per meter per kelvin and ambipolar mobility of 1600 centimeters squared per volt per second at the same locations on c-BAs samples at room temperature despite spatial variations. Ab initio calculations show that lowering ionized and neutral impurity concentrations is […]
Tag Archives: semiconductors
Surprising semiconductor properties revealed with innovative new method
Phys.org March 1, 2022 An international team of researchers (USA – PNNL, UT Arlington) tested germanium in combination with a specialized thin crystalline film of lanthanum-strontium-zirconium-titanium-oxide (LSZTO) using hard X-ray photoelectron spectroscopy which can penetrate the material and generate information at the atomic level. They found that the oxygen atoms near the interface donate electrons to the LSZTO film, creating holes in the germanium within a few atomic layers of the interface. These specialized holes resulted in behavior that totally eclipsed the semiconducting properties of both n- and p-type germanium in the different samples they prepared. According to the researchers […]
Ultrathin semiconductors are electrically connected to superconductors for the first time
Phys.org July 6, 2021 For future applications in electronics and quantum technology, researchers are focusing on the development of new components that consist of monolayer semiconducting material. An international team of researchers (Switzerland, Japan) has demonstrated superconducting vertical interconnect access (VIA) contacts to a monolayer of molybdenum disulfide (MoS2) using MoRe as a contact material. The electron transport was mostly dominated by a single superconductor/normal conductor junction with a clear superconductor gap. They found MoS2 regions that are strongly coupled to the superconductor resulting in resonant Andreev tunneling and junction-dependent gap characteristics, suggesting a superconducting proximity effect. Magnetoresistance measurements showed […]
Lead halide perovskites – a horse of a different color
Nanowerk June 7, 2021 To capture the full range of the photophysical processes that occur in metal halide perovskites an international team of researchers (Sweden, Russia, Germany) has developed a novel spectroscopic technique for the study of charge carrier dynamics in lead halide perovskites. This methodology is based on the complete mapping of the photoluminescence quantum yield and decay dynamics in the 2D space of both fluence and frequency of the excitation light pulse. They offer a complete representation of the sample’s photo physics, allow examining the validity of theories by applying a single set of theoretical equations and parameters to […]
Extensive review of spin-gapless semiconductors: Next-generation spintronics candidates
EurekAlert June 26, 2020 The spin‐gapless semiconductors (SGSs) are a new class of zero‐gap materials which have fully spin polarized electrons and holes. They bridge the zero‐gap materials and the half‐metals. The band structures of the SGSs can have two types of energy dispersion: Dirac linear dispersion and parabolic dispersion. Researchers in Australia review both methods in different material systems and the concepts of the SGS, novel spin and charge states, and the potential applications of SGSs in next‐generation spintronic devices…read more. TECHNICAL ARTICLE
Novel MOF is potential next-gen semiconductor
Phys.org March 23, 2020 Researchers at Clemson University constructed a novel double-helical MOF (dhMOF) by introducing a new butterfly-shaped electron-rich π-extended tetrathiafulvalene ligand equipped with four benzoate groups (ExTTFTB). To create a charge transport pathway capable of conducting electricity, they diffused iodine vapor into the porous MOF, causing one strand to become electron deficient while the other remained electron rich. Electrical conductivity surged from 10–8 S/m up to 10–4 S/m range after iodine treatment. Thus, the introduction of the electron-rich ExTTFTB ligand afforded a novel double-helical MOF architecture featuring ovoid cavities and unique charge-delocalization pathways and delivered a new tool […]
Van der Waals magnets, a material for future semiconductors
Nanowerk February 16, 2020 When van der Waals materials are combined with other 2D materials, they can create new materials that show previously undiscovered properties. However, most van der Waals magnetic materials have some constraints in terms of spintronics application because of their low Curie temperature and high coercivity making them unsuitable for use in certain devices. An international team of researchers (South Korea, USA – Brookhaven National Laboratory, Lawrence Berkeley National Laboratory) found that Fe3–xGeTe2 nanoflakes show a significant suppression of the magnetic anisotropy with hole doping. Electronic structure measurements and calculations revealed that the chemical potential shift associated […]
Chipmakers Test Ferroelectrics as a Route to Ultralow-Power Chips
IEEE Spectrum February 26, 2018 Researchers at a company in the US chose a ferroelectric material that does not require ions or atoms to relocate which slows things down in ferroelectric materials. In their experimental 14-nm transistors, clouds of electrons around silicon-doped hafnium dioxide experience the polarization. Ring oscillators made with these transistors can switch at the same frequency as those made with the usual recipe, yet they require just 54 mV to achieve a tenfold increase in the current. Their devices require a 3- to 8-nm-thick layer of ferroelectric material, which is still relatively thick… read more. Related TECHNICAL […]