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High-efficiency metal-semiconductor-metal photodetectors on heteroepitaxially grown Ge on Si

2006; Optica Publishing Group; Volume: 31; Issue: 17 Linguagem: Inglês

10.1364/ol.31.002565

1539-4794

Ali K. Okyay, Ammar Nayfeh, Krishna C. Saraswat, T. Yonehara, Ann F. Marshall, Paul C. McIntyre,

Nanowire Synthesis and Applications

We demonstrate extremely efficient germanium-on-silicon metal-semiconductor-metal photodetectors with responsivities (R) as high as 0.85 A/W at 1.55 μm 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.