High-efficiency metal-semiconductor-metal photodetectors on heteroepitaxially grown Ge on Si.
We demonstrate extremely efficient germanium-on-silicon metal-semiconductor-metal photodetectors with responsivities (R) as high as 0.85 A/W at 1.55 microm and 2V reverse bias. Ge was directly grown on Si by using a novel heteroepitaxial growth technique, which uses multisteps of growth and hydrogen annealing to reduce surface roughness and threading dislocations that form due to the 4.2% lattice mismatch. Photodiodes on such layers exhibit reverse dark currents of 100 mA/cm2 and external quantum efficiency up to 68%. This technology is promising to realize monolithically integrated optoelectronics.
Okyay
Ali K
AK
Center for Integrated Sysmstems, Stanford University, Stanford, California 94305, USA. aokyay@stanford.edu
Nayfeh
Ammar M
AM
Saraswat
Krishna C
KC
Yonehara
Takao
T
Marshall
Ann
A
McIntyre
Paul C
PC