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Silicon-based heterojunction (SHJ) solar cells demonstrate high efficiencies over their homojunction counterparts, revealing the potential of such technologies. We present here the first steps towards the development of molybdenum disulfide (MoS2)/c-silicon heterojunction solar cells, consisting of a preliminary study of the MoS2 material and numerical device simulations of MoS2/Si heterojunction solar cells, using SILVACO ATLAS. Through the optical and structural characterization of MoS2/SiO2/Si samples, we found a significant sensitivity of the MoS2 to ambient oxidation. Optical ellipsometry showed a bandgap of 1.87 eV for a 7 monolayer thick MoS2 sample, suitable for the targeted application. Finally, we briefly introduce a device simulation and show that the MoS2/Si heterojunction could lead to a gain in quantum efficiency, especially in the region with short wavelengths, compared with a standard a-Si/c-Si solar cell. [ABSTRACT FROM AUTHOR]

Fermi level pinning at metal/semiconductor interfaces forbids a total control over the Schottky barrier height. 2D materials may be an interesting route to circumvent this problem. As they weakly interact with their substrate through Van der Waals forces, deposition of 2D materials avoids the formation of the large density of state at the semiconductor interface often responsible for Fermi level pinning. Here, we demonstrate the possibility to alleviate Fermi-level pinning and reduce the Schottky barrier height by the association of surface passivation of germanium with the deposition of 2D graphene. [ABSTRACT FROM AUTHOR]