Fast time response from Si–SiGe undulating layer superlattices

Abstract

We have grown Si–Si1−xGex undulating layer superlattices with x=0.39 and 0.45 by molecular-beam epitaxy on top of epitaxial implanted CoSi2 layers and fabricated vertical metal–semiconductor–metal detectors. The detectors show a quantum efficiency of 5% for the wavelength of 1320 nm and 0.9% for 1550 nm. We performed temporal response measurements, using a Ti:sapphire laser and an optical parametric oscillator which generates ultrafast pulses at infrared wavelengths. An electrical response time of 16 ps full width at half maximum was obtained at a wavelength of 1300 nm.