Intermediate band solar cells hold the promise of ultrahigh power conversion efficiencies using a single semiconductor junction. Many current implementations use materials with bandgaps too small to achieve maximum efficiency or use cost-prohibitive substrates. Here we demonstrate a material system for intermediate band solar cells using InGaN/GaN quantum-dot-in-nanowire heterostructures grown directly on silicon to provide a lower cost, large-bandgap intermediate band solar cell platform. We demonstrate sequential two-photon current generation with sub-bandgap photons, the hallmark of intermediate band solar cell operation, through vertically stacked quantum dots in the nanowires. Near-infrared light biasing with an 850 nm laser intensity up to 200 W/cm² increases the photocurrent above and below the bandgap by up to 19% at 78 K, and 44% at room temperature. The nanostructured III-nitride strategy provides a route towards realistic room temperature intermediate band solar cells while leveraging the cost benefits of silicon substrates.

使用单个半导体结，中频带太阳能电池有望实现超高功率转换效率。许多当前的实现方式使用带隙太小的材料而无法实现最大效率，或者使用成本过高的基板。在这里，我们演示了使用直接在硅上生长的InGaN / GaN纳米点量子线异质结构的中带太阳能电池的材料系统，以提供低成本，大带隙的中带太阳能电池平台。我们通过纳米带中垂直堆叠的量子点，演示了具有子带隙光子的连续双光子电流产生，这是中带太阳能电池操作的标志。850 nm激光强度的近红外光偏置高达200 W / cm ²在78 K时，带隙以上和以下的光电流最多增加19％，在室温下增加44％。纳米结构的III族氮化物策略提供了一条通往现实的室温中带太阳能电池的途径，同时利用了硅基板的成本优势。