Investigation of nonradiative transition processes in p- and n-type silicon single crystals by piezoelectric photothermal spectroscopy

Abstract

The piezoelectric photothermal spectroscopy (PPTS) technique was used to study the nonradiative excitation/deexcitation process in p- and n-type single crystal silicon. The effectiveness of PPTS to investigate surface states and bulk properties of single crystal silicon has been demonstrated. PPTS measurements were conducted on p- and n-type, 〈100〉 orientation, single crystal silicon samples. A broad peaked signal around 1.18±0.01 eV at room temperature showed the characteristics of slow surface states present on a silicon surface. One more signal bearing a peak around 1.07±0.005 eV was due to bulk effect. The PPTS measurements conducted at various temperatures revealed band-to-band and valence band-to-excitons states’ transition with phonon assistance. The measurements at 4.2 and 110 K resolved four types of phonon participation. A good agreement between theoretical expressions and experimental data substantiates our findings that our proposed technique is useful to investigate phonon contribution in the absorption edge for rather thin semiconductor samples.