Photoluminescence and electroluminescence study of SiSi0.7Ge0.3 quantum dots

50 nm quantum dots have been fabricated from MBE grown structures with 15 periods of 3 nm-Si-3 nm-Si0.7Ge0.3 superlattices sandwiched between a Si substrate with a 70 nm undoped buffer layer and a 42 nm Si capping layer using electron beam patterning and reactive ion etching. Studies by electroluminescence (EL) and photoluminescence (PL) at temperatures between 4.2 K and room temperature show that both the EL and PL efficiencies were improved by more than two orders of magnitude relative to the as-grown superlattice structures. Efficient EL is observed even at room temperature.