基于氧化镓异质结二极管的高温氢气传感器

中文摘要 AI 辅助

Ga2O3器件的长期高温运行是广泛采用该技术之前必须克服的关键障碍，但现有研究在很大程度上忽略了这一点。迄今为止的演示表明，器件要么受限于材料或掺杂剂的不稳定性，导致性能随时间退化。在此，我们制备了基于Pt肖特基和Cr2O3/Ga2O3 p-n二极管（Mg掺杂和N掺杂）的Ga2O3基氢气传感器，并在600°C下评估了其800至1,800小时的长期稳定性，期间循环暴露于N2和低浓度H2（500-1,500 ppm）。采用瞬态电流密度（在-0.1 V下测量）和周期性J-V表征来跟踪性能。尽管传感器信号和灵敏度逐渐下降，但器件在整个运行周数内仍能区分氢气浓度。退化具有架构依赖性：Cr2O3:Mg逐渐退化，与已知的Mg迁移一致；Pt肖特基二极管在1,000小时后表现出剧烈变化；而Cr2O3:N在800小时失效前表现出最低但最稳定的性能。热电子发射和基于Lambert W的建模证实，氢气暴露通过质子诱导偶极机制降低界面势垒高度，该机制对两种二极管类型均适用。对老化Pt肖特基二极管的TEM分析揭示了Pt晶粒长大和微孔形成是关键的退化机制。TOF-SIMS证实氮掺杂剂保持在Cr2O3:N层内，支持N掺杂作为Mg掺杂的稳定但性能较低的替代方案。

英文摘要

Long-term, high temperature operation of Ga2O3 devices is a crucial hurdle that must be overcome before widespread adoption of the technology can be achieved, but is largely absent from the overall body of work. Demonstrations up to this point show devices are either limited by material or dopant instability that leads to performance degradation with time. Herein, Ga2O3-based hydrogen sensors employing Pt Schottky and Cr2O3/Ga2O3 p-n diodes (Mg- and N-doped) were fabricated and evaluated for long-term stability at 600C for 800-1,800 hours, with cyclic exposure to N2 and low-concentration H2 (500-1,500 ppm). Transient current density (measured at -0.1 V) and periodic J-V characterization were used to track performance. Despite gradual declines in sensor signal and sensitivity, devices distinguished hydrogen concentrations throughout weeks of operation. Degradation was architecture-dependent: Cr2O3:Mg degraded gradually, consistent with known Mg migration; the Pt Schottky diode showed dramatic changes after 1,000 hours; and Cr2O3:N showed the lowest but most stable performance before failing at 800 hours. Thermionic emission and Lambert W-based modeling confirmed hydrogen exposure reduces interfacial barrier height via a proton-induced dipole mechanism common to both diode types. TEM of aged Pt Schottky diodes revealed Pt grain growth and microvoid formation as key degradation mechanisms. TOF-SIMS confirmed nitrogen dopants remain confined to the Cr2O3:N layer, supporting N-doping as a stable, lower-performance alternative to Mg-doping

发表机构

• Materials Science Center, National Laboratory of the Rockies（国家落基山实验室材料科学中心）
• Department of Metallurgical and Materials Engineering, Colorado School of Mines（科罗拉多矿业学院冶金与材料工程系）

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