Microstructure and optical properties of Ge(Si) dots grown on Si

The microstructural, luminescence properties and photoresponse of multilayer Ge(Si) quantum dots grown on Si (100) substrates are studied. The strain and composition of the dots are studied by synchrotron-radiation x-ray. The dots are found to be Si0.58Ge0.42 alloy with 50% strain relaxed in average. The photoluminescence from the dots is observed up to room temperature. The thermal stability of the quantum dots is studied. P-i-n structures are grown with Ge(Si) dots embedded in the i-layer for photodetection investigation. The photoresponse wavelength of Ge(Si) dots covers the wavelength range of 1.3-1.52 mm and relatively high external quantum efficiency is obtained.