We focus on the optimization of SiGe material deposition, the minimization of the parasitic capacitance of the probe pads for high speed, low voltage and high contrast ratio operation. The device fabrication is based ...We focus on the optimization of SiGe material deposition, the minimization of the parasitic capacitance of the probe pads for high speed, low voltage and high contrast ratio operation. The device fabrication is based on processes for standard Si electronics and is suitable for mass-production. We present observations of quantum confinement and quantum-confined Stark effect （QCSE） electroabsorption in Ge quantum wells （QWs） with SiGe barriers grown on Si substrates. Though Ge is an indirect gap semiconductor, the resulting effects are at least as clear and strong as seen in typical III-V QW structures at similar wavelengths. We also demonstrated a modulator, with eye diagrams of up to 3.5 GHz, a small driving voltage of 2.5 V and a modulation bandwidth at about 10 GHz. Finally, carrier dynamics under ultra-fast laser excitation and high- speed photocurrent response are investigated.展开更多
Germanium （Ge） has gained much interest due to the potential of becoming a direct band gap material and an efficient light source for the future complementary metal-oxide-semiconductor （CMOS） compatible photonic i...Germanium （Ge） has gained much interest due to the potential of becoming a direct band gap material and an efficient light source for the future complementary metal-oxide-semiconductor （CMOS） compatible photonic integrated circuits. In this paper, highly biaxial tensile strained Ge quantum wells （QWs） and quantum dots （QDs） grown by molecular beam epitaxy are presented. Through relaxed step-graded InGaAs buffer layers with a larger lattice constant, up to 2.3% tensile-strained Ge QWs as well as up to 2.46% tensile-strained Ge QDs are obtained. Characterizations show the good material quality as well as low threading dislocation density. A strong increase of photoluminescence （PL） with highly tensile strained Ge layers at low temperature suggests the existence of a direct band gap semiconductor.展开更多
文摘We focus on the optimization of SiGe material deposition, the minimization of the parasitic capacitance of the probe pads for high speed, low voltage and high contrast ratio operation. The device fabrication is based on processes for standard Si electronics and is suitable for mass-production. We present observations of quantum confinement and quantum-confined Stark effect （QCSE） electroabsorption in Ge quantum wells （QWs） with SiGe barriers grown on Si substrates. Though Ge is an indirect gap semiconductor, the resulting effects are at least as clear and strong as seen in typical III-V QW structures at similar wavelengths. We also demonstrated a modulator, with eye diagrams of up to 3.5 GHz, a small driving voltage of 2.5 V and a modulation bandwidth at about 10 GHz. Finally, carrier dynamics under ultra-fast laser excitation and high- speed photocurrent response are investigated.
文摘Germanium （Ge） has gained much interest due to the potential of becoming a direct band gap material and an efficient light source for the future complementary metal-oxide-semiconductor （CMOS） compatible photonic integrated circuits. In this paper, highly biaxial tensile strained Ge quantum wells （QWs） and quantum dots （QDs） grown by molecular beam epitaxy are presented. Through relaxed step-graded InGaAs buffer layers with a larger lattice constant, up to 2.3% tensile-strained Ge QWs as well as up to 2.46% tensile-strained Ge QDs are obtained. Characterizations show the good material quality as well as low threading dislocation density. A strong increase of photoluminescence （PL） with highly tensile strained Ge layers at low temperature suggests the existence of a direct band gap semiconductor.
