The cover photo describing the crystal structure of Na5YSi4O12 with glass-ceramic Na+ superionic conductors. As discussed by Toshinori Okura, these glass-ceramic conductors have great potential and are one of the most important groups of solid electrolytes, not only because of its practical usefulness for advanced batteries but also for its three-dimensional ionic conducting nature.
Increasing the efficiency of graphene-based Schottky-barrier devices
Shuo-En Wu, Ya-Ping Hsieh*
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 11617, Taiwan
Adv. Mater. Lett., 2019, 10 (2), pp 132-135
Publication Date (Web): Dec 19, 2018
Copyright © 2018 VBRI Press
Graphene’s high carrier mobility and ambipolar nature has the potential to improve electronic devices. The absence of a band-gap necessitates heterostructure devices. Schottky-barrier devices consisting of an interface between graphene and a semiconductor represent the simplest heterostructure. Despite its simplicity, graphene-based Schottky barrier devices are not well understood and exhibit low injection efficiencies. We here investigate the impact of graphene/metal interaction on the properties of the Schottky-barrier. Besides the commonly employed Au/graphene we use Pt/graphene contacts. We find that the injection efficiency for Pt is 5x higher than for Au and systematically study the origin of this behavior. We identify a large difference in Richardson’s constant due to changes in the density of surface states. The demonstrated ability to increase the injection current was applied to improve the efficiency of graphene-based Schottky solar cells by 13x.
Graphene, schottky barrier, richardson, solar cell.