We report uniaxial tensile strains up to 5.7%along h100i in suspended germanium(Ge)wires on a silicon substrate,measured using Raman spectroscopy.This strain is sufficient to make Ge a direct bandgap semiconductor.The...We report uniaxial tensile strains up to 5.7%along h100i in suspended germanium(Ge)wires on a silicon substrate,measured using Raman spectroscopy.This strain is sufficient to make Ge a direct bandgap semiconductor.Theoretical calculations show that a significant fraction of electrons remain in the indirect conduction valley despite the direct bandgap due to the much larger density of states;however,recombination can nevertheless be dominated by radiative direct bandgap transitions if defects are minimized.We then calculate the theoretical efficiency of direct bandgap Ge LEDs and lasers.These strained Ge wires represent a direct bandgap Group IV semiconductor integrated directly on a silicon platform.展开更多
基金This work was supported by the U.S.Government through APIC Corporation(Dr.Raj Dutt),by the AFOSR MURI on Integrated Hybrid Nanophotonic Circuits(Grant No.FA9550-12-1-0024)by a Stanford Graduate Fellowship.
文摘We report uniaxial tensile strains up to 5.7%along h100i in suspended germanium(Ge)wires on a silicon substrate,measured using Raman spectroscopy.This strain is sufficient to make Ge a direct bandgap semiconductor.Theoretical calculations show that a significant fraction of electrons remain in the indirect conduction valley despite the direct bandgap due to the much larger density of states;however,recombination can nevertheless be dominated by radiative direct bandgap transitions if defects are minimized.We then calculate the theoretical efficiency of direct bandgap Ge LEDs and lasers.These strained Ge wires represent a direct bandgap Group IV semiconductor integrated directly on a silicon platform.
