Poly(vinylpyrrolidone)-stabilized silver nanoparticles for strained-silicon surface enhanced Raman spectroscopy

Poly(vinylpyrrolidone)-stabilized silver nanoparticles deposited onto strained-silicon layers grown on graded Si_1-xGe_x virtual substrates are utilized for selective amplification of the Si-Si vibration mode of strained silicon via surface-enhanced Raman scattering spectroscopy. This solution-based technique allows rapid, highly sensitive and accurate characterization of strained silicon whose Raman signal would usually be overshadowed by the underlying bulk SiGe Raman spectra. The analysis was performed on strained silicon samples of thickness 9, 17.5 and 42 nm using a 488 nm Ar⁺ micro-Raman excitation source. The quantitative determination of strained-silicon enhancement factors was also made.