28Si30Si

28Si30Si refers to a silicon crystal that has been isotopically enriched with specific silicon isotopes. Naturally occurring silicon is a mixture of three stable isotopes: 28Si, 29Si, and 30Si. The relative abundance of these isotopes is approximately 92.23% for 28Si, 4.68% for 29Si, and 3.09% for 30Si. 28Si30Si specifically denotes a material where the proportion of 30Si has been significantly increased, and the proportion of 28Si may also be adjusted relative to the natural abundance. This enrichment is achieved through sophisticated isotopic separation techniques, often involving gaseous diffusion or centrifugation.

The primary application of isotopically enriched silicon like 28Si30Si lies in scientific research and advanced technological fields. For instance, highly pure and isotopically defined silicon is crucial for fundamental metrology, such as defining the kilogram unit through precise measurements of silicon spheres. In semiconductor research, altering the isotopic composition can influence material properties like thermal conductivity and neutron scattering cross-sections, which can be beneficial for developing specialized electronic devices or for nuclear applications. The study of isotopic effects in materials science also relies on such enriched samples to understand how variations in atomic nuclei affect macroscopic properties.