Sampayan S E, Grivickas P V, Conway A M, Sampayan K C, Booker I, Bora M, Caporaso G J, Grivickas V, Nguyen H T, Redeckas K, Schoner A, Voss L F, Vengris M, Wang L
Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94551, USA.
Opcondys Incorporated, 600 Commerce Court, Manteca, CA, 95336, USA.
Sci Rep. 2021 Mar 25;11(1):6859. doi: 10.1038/s41598-021-85275-6.
Unabated, worldwide trends in CO production project growth to > 43-BMT per year over the next two decades. Efficient power electronics are crucial to fully realizing the CO mitigating benefits of a worldwide smart grid (~ 18% reduction for the United States alone). Even state-of-the-art SiC high voltage junction devices are inefficient because of slow transition times (~ 0.5-μs) and limited switching rates at high voltage (~ 20-kHz at ≥ 15-kV) resulting from the intrinsically limited charge carrier drift speed (< 2 × 10-cm-s). Slow transition times and limited switch rates waste energy through transition loss and hysteresis loss in external magnetic components. Bulk conduction devices, where carriers are generated and controlled nearly simultaneously throughout the device volume, minimize this loss. Such devices are possible using below bandgap excitation of semi-insulating (SI) SiC single crystals. We explored carrier dynamics with a 75-fs single wavelength pump/supercontinuum probe and a modified transient spectroscopy technique and also demonstrated a new class of efficient, high-speed, high-gain, bi-directional, optically-controlled transistor-like power device. At a performance level six times that of existing devices, for the first time we demonstrated prototype operation at multi-10s of kW and 20-kV, 125-kHz in a bulk conduction transistor-like device using direct photon-carrier excitation with below bandgap light.
在全球范围内，一氧化碳（CO）产量呈持续增长趋势，预计在未来二十年内每年将超过430亿吨。高效的电力电子技术对于充分实现全球智能电网的CO减排效益至关重要（仅美国就可减少约18%）。即使是最先进的碳化硅（SiC）高压结型器件也效率低下，这是由于本征电荷载流子漂移速度有限（<2×10⁷cm/s）导致的转换时间缓慢（约0.5微秒）以及高电压下开关速率受限（≥15 kV时约20 kHz）。缓慢的转换时间和有限的开关速率会通过外部磁性元件中的转换损耗和磁滞损耗浪费能量。体传导器件可使载流子在整个器件体积内几乎同时产生和控制，从而将这种损耗降至最低。利用半绝缘（SI）SiC单晶的带隙以下激发可以实现这类器件。我们使用75飞秒单波长泵浦/超连续谱探针和改进的瞬态光谱技术探索了载流子动力学，并展示了一种新型的高效、高速、高增益、双向、光控晶体管型功率器件。在性能水平比现有器件高出六倍的情况下，我们首次在一个体传导晶体管型器件中，使用带隙以下光的直接光子 - 载流子激发，展示了在数十千瓦、20 kV、125 kHz下的原型运行。
