Semimetal hR6-CaSi2 thin film: A transparent contact for Si optoelectronics

Textured Stainless Steel as a Platform for Black Mg2Si/Si Heterojunction Solar Cells with Advanced Photovoltaic Performance

“…To explore, in depth, the Si-compatible technology paradigm, we implemented the recently described concept of using a semimetal calcium disilicide top electrode [ 30 ]. Briefly, CaSi 2 demonstrates a high figure of merit as a transparent conducting material, while its constituents are non-toxic and earth abundant.…”

“…This explained the increase in total reflection, presented in Figure 4 b. We speculated that the higher VIS reflection may have resulted from the transparency window of the CaSi 2 lying in the spectral range of 550–2000 nm [ 30 ]. Nonetheless, the CaSi 2 cover successfully fulfilled the requirements of both low sheet resistance (~35 Ω/sq.)…”

“…The resultant SS/Fe 3 O 4 /Si templates demonstrated competitive antireflection properties without needing to deposit any intermediate layers. In addition, we further exploited our concepts of the black silicide [ 29 ], which deals with semiconducting magnesium silicide (Mg 2 Si) formation atop a textured Si surface, and optically transparent calcium disilicide (CaSi 2 ) [ 30 ] that acts as a top electrode, to demonstrate a prototype Si-silicide heterojunction solar cell (HSC) with the black-SS/Fe 3 O 4 /Si/Mg 2 Si/CaSi 2 structure. The former concept is devoted to the silicidation of the Si surface textures, which results in the preservation of the original morphology, while providing unprecedented near-infrared (NIR) antireflection performance.…”

Ca silicide films—promising materials for silicon optoelectronics

“…39) The most important factor that was previously discovered in polycrystalline CaSi 2 films is a combination of high conductivity and sufficiently high transparency in the IR range. [39][40][41] In fact, a relatively thick (130 nm) hR6-CaSi 2 film was characterized by an optical transparency no worse than 20% in the NIR and MIR spectral ranges, reaching a transmittance of 47% at a wavelength of 1550 nm and maintaining a low specific electric (87 μΩ × cm) and sheet (6.6 Ω/□) resistances at room temperature. [39][40][41] It has been shown that hR6-CaSi 2 films on silicon, having a high standardized quality factor of 0.2 Ω −1 , are suitable for silicon-based optoelectronics, competing with other modern transparent conductive materials, such as ITO (indium-tin oxide).…”

“…[39][40][41] In fact, a relatively thick (130 nm) hR6-CaSi 2 film was characterized by an optical transparency no worse than 20% in the NIR and MIR spectral ranges, reaching a transmittance of 47% at a wavelength of 1550 nm and maintaining a low specific electric (87 μΩ × cm) and sheet (6.6 Ω/□) resistances at room temperature. [39][40][41] It has been shown that hR6-CaSi 2 films on silicon, having a high standardized quality factor of 0.2 Ω −1 , are suitable for silicon-based optoelectronics, competing with other modern transparent conductive materials, such as ITO (indium-tin oxide). 42,43) The CaSi 2 film grown on a sapphire substrate demonstrated optical transparency in the visible region.…”