20 research outputs found
Ultrathin Stable Ohmic Contacts for High-Temperature Operation of -GaO Devices
Beta gallium oxide (-GaO) shows significant promise in the
high-temperature, high-power, and sensing electronics applications. However,
long-term stable metallization layers for Ohmic contacts at high temperature
present unique thermodynamic challenges. The current most common Ohmic contact
design based on 20 nm of Ti has been repeatedly demonstrated to fail at even
moderately elevated temperatures (300-400C) due to a combination of
non-stoichiometric Ti/GaO interfacial reactions and kinetically favored
Ti diffusion processes. Here we demonstrate stable Ohmic contacts for
GaO devices operating up to 500-600C using ultrathin Ti
layers with a self-limiting interfacial reaction. The ultrathin Ti layer in the
5nm Ti / 100nm Au contact stack is designed to fully oxidize while forming an
Ohmic contact, thereby limiting both thermodynamic and kinetic instability.
This novel contact design strategy results in an epitaxial conductive anatase
titanium oxide interface layer that enables low-resistance Ohmic contacts that
are stable both under long-term continuous operation (>500 hours) at
600C in vacuum ( 10 Torr), as well as after repeated
thermal cycling (15 times) between room temperature and 550C in
flowing N. This stable Ohmic contact design will accelerate the development
of high-temperature devices by enabling research focus to shift towards
rectifying contacts and other interfacial layers.Comment: 25 Pages, 7 Figure
Roadmap on inorganic perovskites for energy applications
Authors thank EPSRC (EP/P007821/1) and Low Emissions Resources Global for support.Inorganic perovskites exhibit many important physical properties such as ferroelectricity, magnetoresistance and superconductivity as well their importance as Energy Materials. Many of the most important energy materials are inorganic perovskites and find application in batteries, fuel cells, photocatalysts, catalysis, thermoelectrics and solar thermal. In all these applications, perovskite oxides, or their derivatives offer highly competitive performance, often state of the art and so tend to dominate research into energy material. In the following sections, we review these functionalities in turn seeking to facilitate the interchange of ideas between domains. The potential for improvement is explored and we highlight the importance of both detailed modelling and in situ and operando studies in taking these materials forward.Publisher PDFPeer reviewe
Roadmap on exsolution for energy applications
Over the last decade, exsolution has emerged as a powerful new method for decorating oxide supports with uniformly dispersed nanoparticles for energy and catalytic applications. Due to their exceptional anchorage, resilience to various degradation mechanisms, as well as numerous ways in which they can be produced, transformed and applied, exsolved nanoparticles have set new standards for nanoparticles in terms of activity, durability and functionality. In conjunction with multifunctional supports such as perovskite oxides, exsolution becomes a powerful platform for the design of advanced energy materials. In the following sections, we review the current status of the exsolution approach, seeking to facilitate transfer of ideas between different fields of application. We also explore future directions of research, particularly noting the multi-scale development required to take the concept forward, from fundamentals through operando studies to pilot scale demonstrations