Effect of uniaxial-strain on Ge p-i-n photodiodes integrated on Si

Abstract

We demonstrate the effect of uniaxial tensile and compressive strain in Ge p-i-n photodiode integrated on Si using four-point bending structures. Responsivity at 1550 nm is increased from 0.67 to 0.75 A/W by tensile strain in the ⟨110⟩ direction while for compressive strain it decreases from 0.67 to 0.477 A/W. These uniaxial tensile and compressive strains also effectively result in shifts of the absorption spectra toward longer and shorter wavelength as they reduce or increase the direct bandgap energy of the Ge layer, respectively.