Study of valence band structure of silicon by ftir at liquid helium temperatures

IR absorption measurements of FZ grown and boron doped silicon single crystals at liquid helium temperatures by spectra amplification technique of FTIR, revealed the existance of three bands in the 3000–2800 cm region superimposed upon broad absorption by free carriers. Deconvolution of these bands further showed some other weak bands. These bands are attributed to transitions involving valence sub-bands and spin orbit splitting of silicon.