We investigate 1.3μm multi quantum-well (MQW) lasers with InGaAsP (well) and InGaAIAs (barrier) on InP for high speed application,compared to the typical structures of In GaAsP (well)-InGaAsP (barrier)/InP and InGaAl...We investigate 1.3μm multi quantum-well (MQW) lasers with InGaAsP (well) and InGaAIAs (barrier) on InP for high speed application,compared to the typical structures of In GaAsP (well)-InGaAsP (barrier)/InP and InGaAlAs (well)-InGaAlAs (barrier)/InP with the same quaternary in the well and barrier.We calculate the characteristics of band offset and gain of InGaAsP-AlGaInAs quantum wells ( Q Ws).The advances of the new Q W design are mainly rooted in the large ratio between conduction-band and valence-band offsets (△Ec:△Ev =7:1),higher than the typical value of 4:6 in InGaAsP-InGaAsP and 7:3 in InGaAlAs-InGaAlAs for 1.3μm lasers.Due to the 1ow confinement energy of holes,non-uniformity of carrier distribution over multi-InGaAsP-AlGaInAs QWs is significantly reduced.The enhancement of high-speed performance of InGaAsP-AlGaInAs MQW lasers is investigated in terms of turn-on oscillation.展开更多
In order to develop the photodetector for effective blue-green response, the 18-mm-diameter vacuum image tube combined with the transmission-mode Alo.7Gao.3Aso.9Po.1/GaAso.9Po.1 photocathode grown by molecular beam ep...In order to develop the photodetector for effective blue-green response, the 18-mm-diameter vacuum image tube combined with the transmission-mode Alo.7Gao.3Aso.9Po.1/GaAso.9Po.1 photocathode grown by molecular beam epitaxy is tentatively fabricated. A comparison of photoelectric property, spectral characteristic and performance parameter be- tween the transmission-mode GaAsP-based and blue-extended GaAs-based photocathodes shows that the GaAsP-based photocathode possesses better absorption and higher quantum efficiency in the blue-green waveband, combined with a larger surface electron escape probability. Especially, the quantum efficiency at 532 nm for the GaAsP-based photocathode achieves as high as 59%, nearly twice that for the blue-extended GaAs-based one, which would be more conducive to the underwater range-gated imaging based on laser illumination. Moreover, the simulation results show that the favorable blue-green response can be achieved by optimizing the emission-layer thickness in a range of 0.4 μm-0.6 μm.展开更多
The fractal patterns in implanted samples are observed. Possible correlation of fractal patterns with the annealing temperature and the electrical activation ratio are given. The formation and growth process of fracta...The fractal patterns in implanted samples are observed. Possible correlation of fractal patterns with the annealing temperature and the electrical activation ratio are given. The formation and growth process of fractal patterns are compared for implanted layers both in silicon and in SiO2/GaAsP during thermal annealing. The mechanism of formation and growth process of fractal pattern is discussed.展开更多
基金Supported by the Hundred Talents Program of Chinese Academy of SciencesKey Research Project of Fujian Province under Grant No 2011HZ001-3.
文摘We investigate 1.3μm multi quantum-well (MQW) lasers with InGaAsP (well) and InGaAIAs (barrier) on InP for high speed application,compared to the typical structures of In GaAsP (well)-InGaAsP (barrier)/InP and InGaAlAs (well)-InGaAlAs (barrier)/InP with the same quaternary in the well and barrier.We calculate the characteristics of band offset and gain of InGaAsP-AlGaInAs quantum wells ( Q Ws).The advances of the new Q W design are mainly rooted in the large ratio between conduction-band and valence-band offsets (△Ec:△Ev =7:1),higher than the typical value of 4:6 in InGaAsP-InGaAsP and 7:3 in InGaAlAs-InGaAlAs for 1.3μm lasers.Due to the 1ow confinement energy of holes,non-uniformity of carrier distribution over multi-InGaAsP-AlGaInAs QWs is significantly reduced.The enhancement of high-speed performance of InGaAsP-AlGaInAs MQW lasers is investigated in terms of turn-on oscillation.
基金supported by the National Natural Science Foundation of China(Grant No.61301023)the Science and Technology on Low-Light-Level Nigh Vision Laboratory Foundation,China(Grant No.BJ2014001)
文摘In order to develop the photodetector for effective blue-green response, the 18-mm-diameter vacuum image tube combined with the transmission-mode Alo.7Gao.3Aso.9Po.1/GaAso.9Po.1 photocathode grown by molecular beam epitaxy is tentatively fabricated. A comparison of photoelectric property, spectral characteristic and performance parameter be- tween the transmission-mode GaAsP-based and blue-extended GaAs-based photocathodes shows that the GaAsP-based photocathode possesses better absorption and higher quantum efficiency in the blue-green waveband, combined with a larger surface electron escape probability. Especially, the quantum efficiency at 532 nm for the GaAsP-based photocathode achieves as high as 59%, nearly twice that for the blue-extended GaAs-based one, which would be more conducive to the underwater range-gated imaging based on laser illumination. Moreover, the simulation results show that the favorable blue-green response can be achieved by optimizing the emission-layer thickness in a range of 0.4 μm-0.6 μm.
基金Project supported by the National Natural Science Foundation of China.
文摘The fractal patterns in implanted samples are observed. Possible correlation of fractal patterns with the annealing temperature and the electrical activation ratio are given. The formation and growth process of fractal patterns are compared for implanted layers both in silicon and in SiO2/GaAsP during thermal annealing. The mechanism of formation and growth process of fractal pattern is discussed.
