Ge/Si photodiodes with embedded arrays of Ge quantum dots forthe near infrared (1.3–1.5 µm) region

Abstract

A method has been devised for MBE fabrication of p-i-n photodiodes for the spectral range of 1.3–1.5 µm, based on multilayer Ge/Si heterostructures with Ge quantum dots (QDs) on a Si substrate. The sheet density of QDs is 1.2×1012 cm−2, and their lateral size is ∼8 nm. The lowest room-temperature dark current reported hitherto for Ge/Si photodetectors is achieved (2×10−5 A/cm2 at 1 V reverse bias). A quantum efficiency of 3% at 1.3 µm wavelength is obtained.