Crucial role of Si buffer layer quality in the photoluminescence efficiency of strained Si 1− xGe x/Si quantum wells

Abstract

The crucial role of Si buffer layer quality in strained Si 1− x Ge x /Si quantum well structures is investigated in terms of quantum efficiency of luminescence. The close correlation between etch-pit density (EPD) increase and luminescence quenching is presented for the first time. It is shown that strained Si 1− x Ge x /Si quantum wells with a high degree of luminescence efficiency can be obtained only on a high-quality Si buffer layer grown at temperatures higher than 700°C, which gives an EPD lower than 10 6 cm −2.