CSI

Crystalline silicon, often abbreviated c-Si or cSi, is a crystalline form of the element silicon. It differs from amorphous silicon in having long-range periodic order, and from polycrystalline silicon in the extent and nature of grain boundaries. Crystalline silicon exists mainly as two forms: monocrystalline silicon, which is grown as a single crystal, and polycrystalline (multicrystalline) silicon, composed of many small crystals.

Monocrystalline silicon is produced by growing a single crystal using processes such as the Czochralski (CZ) or float-zone method and is typically sliced into wafers for high-performance integrated circuits and solar cells. Polycrystalline silicon is produced by casting or ribbon methods and is cheaper to manufacture but contains grain boundaries that can reduce minority-carrier lifetimes and device efficiency. Silicon has a diamond cubic crystal structure with strong covalent bonds and exhibits a relatively wide indirect bandgap of about 1.12 eV at room temperature.

In electronics and photovoltaics, crystalline silicon is commonly doped with impurities to form n-type or p-type materials, enabling PN junctions used in diodes, transistors, and other devices. Doping agents include phosphorus or arsenic for n-type and boron for p-type. The material’s carrier mobilities, while limited by silicon’s band structure, are sufficient for reliable high-volume device fabrication. Silicon dioxide (SiO2) is widely used as an insulating layer and gate dielectric in MOS technology. Crystalline silicon dominates both the microelectronics and solar industries due to mature fabrication, stability, and abundant supply, though its indirect bandgap limits light emission efficiency for optoelectronic devices.