Normal incident infrared detector using intervalence band absorption of Si/sub 1-x/Ge/sub x//Si multiple quantum wells

The authors report the demonstration of normal incident infrared detection using intervalence-band absorption in Si/sub 1-x/Ge/sub x//Si multiple quantum wells. In this case, the transition occurs between different hole bands due to the mixing of the s-like Gamma -conduction band Bloch state with p-like hole bands, particularly at large k values. This mechanism is different from the previously reported free-carrier absorption process.