Midinfrared photoconductivity of Ge/Si self-assembled quantum dots

We have investigated the midinfrared photoconductivity of Ge/Si self-assemb led quantum dots. The self-assembled quantum dots were grown by ultra-high- vacuum chemical vapor deposition on Si(001). The photoresponse of the p-typ e device exhibits resonances in the midinfrared around 10 mum wavelength. T he resonance of the photocurrent shifts to lower energy as the applied bias increases. The photocurrent is weakly dependent on the incoming polarizati on of the infrared light. The photocurrent is analyzed in terms of bound-to -bound and bound-to-continuum transitions in the valence band. The photocur rent peaks are correlated to the photoluminescence of the device. (C) 2000 American Institute of Physics. [S0003-6951(00)04046-8].