Semiconductors have been used in solar energy conversion for decades based on the photovoltaic effect. An important challenge of photovoltaics is the undesired heat generated within the device. An alternative approach is thermionics, which uses the thermal excitation of electrons from an emitter to a collector across a vacuum gap. If the emitter is a p-type semiconductor, the photogeneration-induced quasi-Fermi level splitting can reduce the effective barrier for electron emission—a mechanism used by a photon enhanced thermionic emission device. Here, we evaluate the prospects of this alternative solar conversion technology considering different semiconductor materials and thermionic device configurations. We also reveal that whether such a device operates in the photon enhanced or purely thermionic mode, depends on the complex interplay among materials properties, device physics and solar concentration level.

几十年来，半导体一直基于光伏效应用于太阳能转换。光伏的一个重要挑战是设备内产生的不希望有的热量。另一种方法是热电子学，它使用电子的热激发从发射极穿过真空间隙到达集电极。如果发射极是 p 型半导体，光生诱导的准费米能级分裂可以降低电子发射的有效势垒——光子增强热电子发射装置使用的一种机制。在这里，我们考虑了不同的半导体材料和热电子器件配置，评估了这种替代太阳能转换技术的前景。我们还揭示了这种设备是在光子增强模式还是纯热电子模式下运行，