Aiming to achieve InAs quantum dots(QDs) with a long carrier lifetime,the effects of Sb component in cap layers on the band alignment of the InAs/GaAsSb QDs have been studied.InAs QDs with high density and uniformity ...Aiming to achieve InAs quantum dots(QDs) with a long carrier lifetime,the effects of Sb component in cap layers on the band alignment of the InAs/GaAsSb QDs have been studied.InAs QDs with high density and uniformity have been grown by molecular beam epitaxy.With increasing Sb composition,the InAs/GaAsSb QDs exhibit a significant redshift and broadening photoluminescence(PL).With a high Sb component of 22%,the longest wavelength emission of the InAs/GaAs_(0.78)Sb_(0.22) QDs occurs at 1.5 μm at room temperature.The power-dependence PL measurements indicate that with a low Sb component of 14%,the InAs/GaAs_(0.86)Sb_(0.14) QDs have a type-Ⅰ and a type-Ⅱ carrier recombination processes,respectively.With a high Sb component of 22%,the InAs/GaAs_(0.78)Sb_(0.22) QDs have a pure type-Ⅱ band alignment,with three type-Ⅱ carrier recombination processes.Extracted from time-resolved PL decay traces,the carrier lifetime of the InAs/GaAs_(0.78)Sb_(0.22) QDs reaches 16.86 ns,which is much longer than that of the InAs/GaAs_(0.86)Sb_(0.14) QDs(2.07 ns).These results obtained here are meaningful to realize high conversion efficiency intermediate-band QD solar cells and other opto-electronic device.展开更多
We report 25 Gb/s high-speed directly modulated ground-state operation of 1.3 μm In As/Ga As quantum dot(QD) lasers grown by molecular beam epitaxy. The active region of the lasers consists of eight layers of p-doped...We report 25 Gb/s high-speed directly modulated ground-state operation of 1.3 μm In As/Ga As quantum dot(QD) lasers grown by molecular beam epitaxy. The active region of the lasers consists of eight layers of p-doped In As QDs with high uniformity and density. Ridge-waveguide lasers with a 3-μm-wide and 300-μm-long cavity show a low threshold current of 14.4 m A at 20°C and high temperature stability with a high characteristic temperature of 1208 K between 20°C and 70°C. Dynamic response measurements demonstrate that the laser has a 3 d B bandwidth of 7.7 GHz at 20°C and clearly opened eye diagrams even at high temperatures up to 75°C under a 25 Gb/s direct modulation rate.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2019YFB1503601 and 2017YFB0405302)the National Natural Science Foundation of China(Grant Nos.61574139 and U1738114)the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA15051200)。
文摘Aiming to achieve InAs quantum dots(QDs) with a long carrier lifetime,the effects of Sb component in cap layers on the band alignment of the InAs/GaAsSb QDs have been studied.InAs QDs with high density and uniformity have been grown by molecular beam epitaxy.With increasing Sb composition,the InAs/GaAsSb QDs exhibit a significant redshift and broadening photoluminescence(PL).With a high Sb component of 22%,the longest wavelength emission of the InAs/GaAs_(0.78)Sb_(0.22) QDs occurs at 1.5 μm at room temperature.The power-dependence PL measurements indicate that with a low Sb component of 14%,the InAs/GaAs_(0.86)Sb_(0.14) QDs have a type-Ⅰ and a type-Ⅱ carrier recombination processes,respectively.With a high Sb component of 22%,the InAs/GaAs_(0.78)Sb_(0.22) QDs have a pure type-Ⅱ band alignment,with three type-Ⅱ carrier recombination processes.Extracted from time-resolved PL decay traces,the carrier lifetime of the InAs/GaAs_(0.78)Sb_(0.22) QDs reaches 16.86 ns,which is much longer than that of the InAs/GaAs_(0.86)Sb_(0.14) QDs(2.07 ns).These results obtained here are meaningful to realize high conversion efficiency intermediate-band QD solar cells and other opto-electronic device.
基金supported by the National Key Research&Development(R&D)Program of China(No.2016YFB0402302)the National Natural Science Foundation of China(Nos.91433206,61574139 and61841403)
文摘We report 25 Gb/s high-speed directly modulated ground-state operation of 1.3 μm In As/Ga As quantum dot(QD) lasers grown by molecular beam epitaxy. The active region of the lasers consists of eight layers of p-doped In As QDs with high uniformity and density. Ridge-waveguide lasers with a 3-μm-wide and 300-μm-long cavity show a low threshold current of 14.4 m A at 20°C and high temperature stability with a high characteristic temperature of 1208 K between 20°C and 70°C. Dynamic response measurements demonstrate that the laser has a 3 d B bandwidth of 7.7 GHz at 20°C and clearly opened eye diagrams even at high temperatures up to 75°C under a 25 Gb/s direct modulation rate.
