Midinfrared photoconductivity in Ge/Si self-assembled quantum dots

We have investigated midinfrared photoconductivity of Ge/Si self-assembled quantum dots. The self-assembled quantum dots were grown by ultra-high-vacu um chemical vapor deposition on Si(001). The photoresponse of the p-type de vice exhibits resonances in the midinfrared around 10 mum wavelength. The p hotocurrent resonances are associated with intraband transitions in the val ence band of the quantum dots. The photocurrent is studied as a function of applied bias and of the polarization of the incoming light. Bound-to-bound and bound-to-continuum transitions are shown to contribute to the photocur rent. The photocurrent peaks are correlated with the photoluminescence of t he device.