Multilayer-Grown Ultrathin Nanostructured GaAs Solar Cells as a Cost-Competitive Materials Platform for III-V Photovoltaics.
Multilayer-Grown Ultrathin Nanostructured GaAs Solar Cells as a Cost-Competitive Materials Platform for III-V Photovoltaics.
复制标题
多层生长的超薄纳米结构 GaAs 太阳能电池作为具有成本竞争力的 III-V 光伏材料平台。
DOI：
10.1021/acsnano.6b07605
复制
发表时间：
2017
期刊：
影响因子：
17.1
通讯作者：
Jongseung Yoon
中科院分区：
文献类型：
--
作者：
B. Gai;Yukun Sun;Haneol Lim;Huandong Chen;J. Faucher;M. Lee;Jongseung Yoon
GaAs太阳能电池在陆地光电子学中的大规模部署要求显著降低用于制备器件质量的外延材料的成本。虽然多层外延生长结合印刷基材料组件已被提出作为一个有前途的路线，以实现这一目标，其实际的实施仍然具有挑战性，由于材料性能的退化，并导致在不同的顺序生长的太阳能电池之间的不均匀的器件性能。在这里，我们报告了一种替代方法，以规避这些限制，使多层生长的GaAs太阳能电池具有均匀的光伏性能。具有300 nm厚的吸收体（即，发射极和基极）通过使用铍作为p型杂质的分子束外延在三叠层可释放多层组件中外延生长。由于抑制了p型掺杂剂的扩散以及显著减少了与GaAs器件配置相关的外延生长时间，因此由各个器件层制造的微型（500 × 500 μm2）GaAs太阳能电池表现出优异的光伏性能和接触特性的均匀性（相对<3%）。采用六边形周期性TiO 2纳米柱和用作金属背表面反射器的垂直p型金属接触的双面光子管理与专门的外延设计一起使寄生光学损失最小化以用于有效的光捕获协同地使得能够显著增强这样的光吸收器的光伏性能，其中，在模拟的AM1.5G照明下，从在三叠层外延组件中生长的420 nm厚的单结GaAs太阳能电池中证明了17.2%的太阳能到电力转换效率。
Large-scale deployment of GaAs solar cells in terrestrial photovoltaics demands significant cost reduction for preparing device-quality epitaxial materials. Although multilayer epitaxial growth in conjunction with printing-based materials assemblies has been proposed as a promising route to achieve this goal, their practical implementation remains challenging owing to the degradation of materials properties and resulting nonuniform device performance between solar cells grown in different sequences. Here we report an alternative approach to circumvent these limitations and enable multilayer-grown GaAs solar cells with uniform photovoltaic performance. Ultrathin single-junction GaAs solar cells having a 300-nm-thick absorber (i.e., emitter and base) are epitaxially grown in triple-stack releasable multilayer assemblies by molecular beam epitaxy using beryllium as a p-type impurity. Microscale (∼500 × 500 μm2) GaAs solar cells fabricated from respective device layers exhibit excellent uniformity (<3% relative) of photovoltaic performance and contact properties owing to the suppressed diffusion of p-type dopant as well as substantially reduced time of epitaxial growth associated with ultrathin device configuration. Bifacial photon management employing hexagonally periodic TiO2 nanoposts and a vertical p-type metal contact serving as a metallic back-surface reflector together with specialized epitaxial design to minimize parasitic optical losses for efficient light trapping synergistically enable significantly enhanced photovoltaic performance of such ultrathin absorbers, where ∼17.2% solar-to-electric power conversion efficiency under simulated AM1.5G illumination is demonstrated from 420-nm-thick single-junction GaAs solar cells grown in triple-stack epitaxial assemblies.