In this work, a hetero-epitaxial Al0.49In0.51As/Ga0.47In0.53 As metamorphic high electron mobility transistor(mHEMT) grown by metal–organic chemical vapor deposition(MOCVD) on p-type silicon substrate has been succes...In this work, a hetero-epitaxial Al0.49In0.51As/Ga0.47In0.53 As metamorphic high electron mobility transistor(mHEMT) grown by metal–organic chemical vapor deposition(MOCVD) on p-type silicon substrate has been successfully demonstrated. A novel AlGaAs/Al As period multiple quantum well(MQW) composite buffer scheme is developed to effectively tune the leakage current from the buffer layer. The quantized room-temperature Hall mobility of the twodimensional electron gas(2DEG) is larger than 7800 cm2/V·s, with an average sheet carrier density of 4.6×1012cm-2.Two-stage electron beam(EB) lithography technology by a JBX-6300 e-beam lithography system is developed to realize a 0.13-μm m HEMT device on Si substrate. A maximum transconductance Gm of up to 854 mS/mm is achieved, and is comparable to that of m HEMT technology on Ga As substrate with the same dimension. The fTand fmax are 135 GHz and120 GHz, respectively.展开更多
Metamorphic Al0.50In0.50As/Ga0.47In0.53As high electron mobility transistors (mHEMTs) grown by Metal Organic ChemicalVapor Deposition (MOCVD) on n-type silicon substrates with introduction of a novel multi-stage buffe...Metamorphic Al0.50In0.50As/Ga0.47In0.53As high electron mobility transistors (mHEMTs) grown by Metal Organic ChemicalVapor Deposition (MOCVD) on n-type silicon substrates with introduction of a novel multi-stage buffering stack scheme havebeen fabricated for the first time. 1.0- m-gate-length depletion-mode mHEMTs with maximum transconductance up to 613mS/mm are achieved. The unity current gain cut-off frequency (fT) and the maximum oscillation frequency (fmax) are 36.9 and55.6 GHz, respectively. This device has the highest fTyet reported for 1.0- m-gate-length HEMTs grown on silicon byMOCVD. Also, this performance is comparable to that of similar GaAs-based mHEMTs. These are encouraging initial resultsleading to the manufacturing potential of integrated high-speed metamorphic devices for logic applications on silicon sub-strates by MOCVD.展开更多
We present an InGaAs metamorphic high electron mobility transistor （mHEMT） grown using Metalorganic Chemical Vapor Deposition （MOCVD） on an n-type silicon substrate with the introduction of an effective multi-stag...We present an InGaAs metamorphic high electron mobility transistor （mHEMT） grown using Metalorganic Chemical Vapor Deposition （MOCVD） on an n-type silicon substrate with the introduction of an effective multi-stage buffering scheme. Fabrication and performance of a high-frequency 0.3μm gate-length depletion-mode A10.s0In0.s0As/Ga0.47In0.53As mHEMT is re- ported for the first time. Using a combined optical and e-beam photolithography technology, submicron mHEMT devices on Si have been achieved. The non-alloyed ohmic contact resistance Rc was as low as 0.065 Ω-mm. A maximum transconductance up to 761 mS/ram was measured. The unity current gain cut-off frequency （fT） and the maximum oscillation frequency （fmax） were 72.8 and 74.5 GHz, respectively. This device has the highest fw yet reported for a 0.3-μm gate-length Si-based mHEMT grown using MOCVD. A high voltage gain, gm/gds, of 40.6 is observed in the device.展开更多
A 1.3μm low-threshold edge-emitting AlGaInAs multiple-quantum-well(MQW) laser with AlInAs-oxide confinement layers is fabricated.The Al-contained waveguide layers upper and low the active layers are oxidized as curre...A 1.3μm low-threshold edge-emitting AlGaInAs multiple-quantum-well(MQW) laser with AlInAs-oxide confinement layers is fabricated.The Al-contained waveguide layers upper and low the active layers are oxidized as current-confined layers using wet-oxidation technique.This structure provides excellent current and optical confinement,resulting in 12.9mA of a low continuous wave threshold current and 0.47W/A of a high slope efficiency of per facet at room temperature for a 5-μm-wide current aperture.Compared with the ridge waveguide laser with the same-width ridge,the threshold current of the AlInAs-oxide confinement laser has decreased by 31.7% and the slope efficiency has increased a little.Both low threshold and high slope efficiency indicate that lateral current confinement can be realized by oxidizing AlInAs waveguide layers.The full width of half maximum angles of the Al-InAs-oxide confinement laser are 21.6° for the horizontal and 36.1° for the vertical,which demonstrate the ability of the AlInAs oxide in preventing the optical field from spreading laterally.展开更多
An optimal structure design of the lattice mismatched GaInP/GaInAs/Ge solar cell with high photoelectric conversion efficiency was proposed. Two-dimensional Bi2Te3/Sb2Te3 nanosheets were prepared by solvothermal synth...An optimal structure design of the lattice mismatched GaInP/GaInAs/Ge solar cell with high photoelectric conversion efficiency was proposed. Two-dimensional Bi2Te3/Sb2Te3 nanosheets were prepared by solvothermal synthesis method used as thermoelectric(TE) functional materials, which is further hybrid with high conductive reduced graphene oxide(rGO) and carbon nanotubes(CNTs). TE film was then fabricated based on above materials. The power factor of the n-type TE film is 19.31 μW/mK2, and the power factor of the p-type TE film is 97.40 μW/mK2. The flexible TE device was integrated with flexible solar cell. Compared with the single photovoltaic(PV) cell, the efficiency of the as-prepared flexible integrated device measured under the AM1.5 illumination is significantly improved. The efficiency of the two parallel tests is increased from 27.26% and 26.59%, to 29.11% and 28.92%, respectively. The increasing ratio reaches 6.7%-8.8%.展开更多
We directly grow a lattice matched GalnP/GalnAs/GalnNAs/Ge （1.88 eVil .42 eVil .05 eV/0.67eV） four-junction （4J） solar cell on a Ge substrate by the metal organic chemical vapor deposition technology. To solve the...We directly grow a lattice matched GalnP/GalnAs/GalnNAs/Ge （1.88 eVil .42 eVil .05 eV/0.67eV） four-junction （4J） solar cell on a Ge substrate by the metal organic chemical vapor deposition technology. To solve the current limit of the GalnNAs sub cell, we design three kinds of anti-reflection coatings and adjust the base region thickness of the GalnNAs sub cell. Developed by a series of experiments, the external quantum efficiency of the GalnNAs sub cell exceeds 80%, and its current density reaches 11.24 mA/cm2. Therefore the current limit of the 4J solar cell is significantly improved. Moreover, we discuss the difference of test results between 4J and GalnP/GalnAs/Ge solar cells under the 1 sun AMO spectrum.展开更多
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.61401373)the Fundamental Research Funds for Central University,China(Grant Nos.XDJK2013B004 and 2362014XK13)the Chongqing Natural Science Foundation,China(Grant No.cstc2014jcyj A40038)
文摘In this work, a hetero-epitaxial Al0.49In0.51As/Ga0.47In0.53 As metamorphic high electron mobility transistor(mHEMT) grown by metal–organic chemical vapor deposition(MOCVD) on p-type silicon substrate has been successfully demonstrated. A novel AlGaAs/Al As period multiple quantum well(MQW) composite buffer scheme is developed to effectively tune the leakage current from the buffer layer. The quantized room-temperature Hall mobility of the twodimensional electron gas(2DEG) is larger than 7800 cm2/V·s, with an average sheet carrier density of 4.6×1012cm-2.Two-stage electron beam(EB) lithography technology by a JBX-6300 e-beam lithography system is developed to realize a 0.13-μm m HEMT device on Si substrate. A maximum transconductance Gm of up to 854 mS/mm is achieved, and is comparable to that of m HEMT technology on Ga As substrate with the same dimension. The fTand fmax are 135 GHz and120 GHz, respectively.
文摘Metamorphic Al0.50In0.50As/Ga0.47In0.53As high electron mobility transistors (mHEMTs) grown by Metal Organic ChemicalVapor Deposition (MOCVD) on n-type silicon substrates with introduction of a novel multi-stage buffering stack scheme havebeen fabricated for the first time. 1.0- m-gate-length depletion-mode mHEMTs with maximum transconductance up to 613mS/mm are achieved. The unity current gain cut-off frequency (fT) and the maximum oscillation frequency (fmax) are 36.9 and55.6 GHz, respectively. This device has the highest fTyet reported for 1.0- m-gate-length HEMTs grown on silicon byMOCVD. Also, this performance is comparable to that of similar GaAs-based mHEMTs. These are encouraging initial resultsleading to the manufacturing potential of integrated high-speed metamorphic devices for logic applications on silicon sub-strates by MOCVD.
基金supported by the CERG(Grant No. 615506) from the Research Grants Council of Hong Kong and Intel Corporation
文摘We present an InGaAs metamorphic high electron mobility transistor （mHEMT） grown using Metalorganic Chemical Vapor Deposition （MOCVD） on an n-type silicon substrate with the introduction of an effective multi-stage buffering scheme. Fabrication and performance of a high-frequency 0.3μm gate-length depletion-mode A10.s0In0.s0As/Ga0.47In0.53As mHEMT is re- ported for the first time. Using a combined optical and e-beam photolithography technology, submicron mHEMT devices on Si have been achieved. The non-alloyed ohmic contact resistance Rc was as low as 0.065 Ω-mm. A maximum transconductance up to 761 mS/ram was measured. The unity current gain cut-off frequency （fT） and the maximum oscillation frequency （fmax） were 72.8 and 74.5 GHz, respectively. This device has the highest fw yet reported for a 0.3-μm gate-length Si-based mHEMT grown using MOCVD. A high voltage gain, gm/gds, of 40.6 is observed in the device.
文摘A 1.3μm low-threshold edge-emitting AlGaInAs multiple-quantum-well(MQW) laser with AlInAs-oxide confinement layers is fabricated.The Al-contained waveguide layers upper and low the active layers are oxidized as current-confined layers using wet-oxidation technique.This structure provides excellent current and optical confinement,resulting in 12.9mA of a low continuous wave threshold current and 0.47W/A of a high slope efficiency of per facet at room temperature for a 5-μm-wide current aperture.Compared with the ridge waveguide laser with the same-width ridge,the threshold current of the AlInAs-oxide confinement laser has decreased by 31.7% and the slope efficiency has increased a little.Both low threshold and high slope efficiency indicate that lateral current confinement can be realized by oxidizing AlInAs waveguide layers.The full width of half maximum angles of the Al-InAs-oxide confinement laser are 21.6° for the horizontal and 36.1° for the vertical,which demonstrate the ability of the AlInAs oxide in preventing the optical field from spreading laterally.
文摘An optimal structure design of the lattice mismatched GaInP/GaInAs/Ge solar cell with high photoelectric conversion efficiency was proposed. Two-dimensional Bi2Te3/Sb2Te3 nanosheets were prepared by solvothermal synthesis method used as thermoelectric(TE) functional materials, which is further hybrid with high conductive reduced graphene oxide(rGO) and carbon nanotubes(CNTs). TE film was then fabricated based on above materials. The power factor of the n-type TE film is 19.31 μW/mK2, and the power factor of the p-type TE film is 97.40 μW/mK2. The flexible TE device was integrated with flexible solar cell. Compared with the single photovoltaic(PV) cell, the efficiency of the as-prepared flexible integrated device measured under the AM1.5 illumination is significantly improved. The efficiency of the two parallel tests is increased from 27.26% and 26.59%, to 29.11% and 28.92%, respectively. The increasing ratio reaches 6.7%-8.8%.
文摘We directly grow a lattice matched GalnP/GalnAs/GalnNAs/Ge （1.88 eVil .42 eVil .05 eV/0.67eV） four-junction （4J） solar cell on a Ge substrate by the metal organic chemical vapor deposition technology. To solve the current limit of the GalnNAs sub cell, we design three kinds of anti-reflection coatings and adjust the base region thickness of the GalnNAs sub cell. Developed by a series of experiments, the external quantum efficiency of the GalnNAs sub cell exceeds 80%, and its current density reaches 11.24 mA/cm2. Therefore the current limit of the 4J solar cell is significantly improved. Moreover, we discuss the difference of test results between 4J and GalnP/GalnAs/Ge solar cells under the 1 sun AMO spectrum.
