A high efficient 820 nm MOS Ge quantum dot photodetector

A Ge quantum dot photodetector has been demonstrated using a metal-oxide-semiconductor (MOS) tunneling structure. The oxide film was grown by liquid phase deposition (LPD) at 50(degree)C. The photodetector with five-period Ge quantum dot has responsivity of 130, 0.16, and 0.08 mA/W at wavelengths of 820 nm, 1300 nm, and 1550 nm, respectively. The device with 20-period Ge quantum dot shows responsivity of 600 mA/W at the wavelength of 850 nm. The room temperature dark current density is as low as 0.06 mA/cm/sup 2/. The high performance of the photodetectors at 820 nm makes it feasible to integrate electrooptical devices into Si chips for short-range optical communication.