Single crystal

About: Single crystal is a research topic. Over the lifetime, 59617 publications have been published within this topic receiving 870828 citations.

Growth Strategy and Physical Properties of the High Mobility P-Type CuI Crystal

Abstract: Acquiring stable binary wide band-gap semiconductor (WBS) materials with high p-type mobility is essential for the development of WBS optoelectronic devices. CuI is a p-type WBS material with a large band gap (3.1 eV) and high exciton binding energy (62 meV). However, the semiconductor characteristics of the CuI single crystal are unknown due to the lack of a large sized and high quality crystal. Our approach focuses on the design of the mineralizer for the hydrothermal method to effectively control the growth habit and the impurity concentration in the crystal. A large size (15 mm × 10 mm × 1 mm) and high quality CuI single crystal is obtained by using a new mineralizer (NH4I + KI). The crystal shows high p-type mobility (43.9 cm2·V−1·S1−). The strong and sharp band-edge emission at 410 nm indicates that the interband excitonic transition dominates the optical response in the spectrum. Such a binary crystalline material may open the way to new applications in optoelectronic devices.

Corundum Structure Oxides Studied by XPS

Abstract: The electronic structure behaviour of Me2O3 oxides (Me = Ti, V, Cr) has been determined from XPS valence band and core level measurements. From Ti to Cr sesquioxide the relative intensity of the 3d band increases systematically which can be explained by the (atomic) photoelectric cross section and the number of 3d electrons. Simultaneously the 3d-2p band separation decreases indicating a more stronger band overlap equivalent an enhanced covalent bonding component. The different electrical properties among the corundum structure oxides are determined by the trigonal field splitted a1g and eg orbitals, their occupation and relative energy position at the Fermi level. The observations confirm the change from itinerant to more localized behaviour of d electrons caused by crystal structure parameter change (c/a ratio).

Pressure-induced superconductivity in CaFe2As2

Abstract: We report pressure-induced superconductivity in a single crystal of CaFe2As2. At atmospheric pressure, this material is antiferromagnetic below 170 K but under an applied pressure of 0.69 GPa becomes superconducting, with a transition temperature Tc exceeding 10 K. The rate of Tc suppression with applied magnetic field is −0.7 K T−1, giving an extrapolated zero-temperature upper critical field of 10–14 T.