In this paper, the integration of metal oxides as carrier-selective contacts for ultrathin crystalline silicon (c-Si) solar cells is demonstrated which results in an ∼13% relative improvement in efficiency. The improvement in efficiency originates from the suppression of the contact recombination current due to the band offset asymmetry of these oxides with Si. First, an ultrathin c-Si solar cell having a total thickness of 2 μm is shown to have >10% efficiency without any light-trapping scheme. This is achieved by the integration of nickel oxide (NiO_x) as a hole-selective contact interlayer material, which has a low valence band offset and high conduction band offset with Si. Second, we show a champion cell efficiency of 10.8% with the additional integration of titanium oxide (TiO_x), a well-known material for an electron-selective contact interlayer. Key parameters including V_oc and J_sc also show different degrees of enhancement if single (NiO_x only) or double (both NiO_x and TiO_x) carrier-selective contacts are integrated. The fabrication process for TiO_x and NiO_x layer integration is scalable and shows good compatibility with the device.

中文翻译：

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使用过渡金属氧化物在2μm厚的超薄c-Si太阳能电池中进行接触选择性工程，可实现10.8％的效率

在本文中，证明了金属氧化物作为超薄晶体硅（c-Si）太阳能电池的载流子选择触点的集成，其效率相对提高了约13％。效率的提高源于由于这些氧化物与Si的带隙不对称导致的接触复合电流的抑制。首先，总厚度为2μm的超薄c-Si太阳能电池在没有任何光捕获方案的情况下显示出> 10％的效率。这是通过将氧化镍（NiO _x）集成为空穴选择性接触层间材料而实现的，该材料具有低价带偏移和高Si导带偏移。其次，通过额外整合二氧化钛（TiO _x），一种电子选择性接触中间层的众所周知的材料。如果集成了单个（仅NiO _x）或双（NiO _x和TiO _x）载流子选择触点，则包括V _oc和J _sc在内的关键参数也显示出不同程度的增强。TiO _x和NiO _x层集成的制造工艺是可扩展的，并且显示出与器件的良好兼容性。