The relatively low Schottky barrier height on In_(0.52)Al_(0.48)As lattice-matched to InP has hampered the achievement of enhancement-mode InA1As/InGaAs/InP high electron mobility transistors(E-HEMTs).By introducing l...The relatively low Schottky barrier height on In_(0.52)Al_(0.48)As lattice-matched to InP has hampered the achievement of enhancement-mode InA1As/InGaAs/InP high electron mobility transistors(E-HEMTs).By introducing lattice mismatched strained aluminum-rich In_(0.45) Al_(0.55)As as the Schottky contact material to enhance the barrier height,we have developed InP-based InAlAs/InGaAs/InP E-HEMT with threshold voltage of about 150 m V.A maximum extrinsic transconductance of 660mS/mm and output conductance of 15mS/mm are measured for 1μm-gate length devices at room temperature.The devices also show excellent radio-frequency performance with cutoff frequency of 50 GHz and maximum oscillation frequency of 54 GHz.展开更多
A functional field effect transistor with self-organized In_(0.15)Ga_(0.85)As/GaAs quantum wires(QWRs)as a channel was achieved by molecular beam epitaxy on a(553)B GaAs substrate.Both the three-dimensional image of a...A functional field effect transistor with self-organized In_(0.15)Ga_(0.85)As/GaAs quantum wires(QWRs)as a channel was achieved by molecular beam epitaxy on a(553)B GaAs substrate.Both the three-dimensional image of atom force microscopy and the polarization of the photoluminance peaks reveal that the channel of the device is a self-organized QWR structure.The device with a gate-length of 2μm and a source-drain spacing of 5μm performed a good enhancement-mode characteristic and a maximum transconductance of 65 mS/mm was obtained at the gate voltage of 1.0 V by the geometric gate-width at room temperature.The saturated drain current is as high as 5.6 mA.The device exhibited a much larger current capacity due to the high density of the self-organized QWRs in its channel layer.In addition,the effective gate width was discussed in comparison with the geometric gate width of the device,from which a larger maximum transconductance of 130 mS/mm could be estimated.展开更多
Room temperature photoluminescence(PL)spectra of InAs self-assembled quantum dots(QDs)deposited on a GaAs/InP and InP substrate are investigated.From the PL spectra,we find that the peak position of InAs QDs appears r...Room temperature photoluminescence(PL)spectra of InAs self-assembled quantum dots(QDs)deposited on a GaAs/InP and InP substrate are investigated.From the PL spectra,we find that the peak position of InAs QDs appears red-shift from 0.795 to 0.785 eV after we insert a thin tensile GaAs layer between InAs QD layer and InP buffer layer.In order to explain this phenomenon in theory,we examine the strain tensor in InAs quantum dots by using a valence force field model and use a five-band k.p formalism to obtain the electronic structure.The calculated results show that the ground transition energy decreases from 0.789 to 0.780 eV when the thin GaAs layer is inserted.Therefore,the PL peak position should appear red-shift as shown in the experiment.展开更多
基金Supported by the High Technology Research and Development Programme of China under Contract 863-307-15-3(6).
文摘The relatively low Schottky barrier height on In_(0.52)Al_(0.48)As lattice-matched to InP has hampered the achievement of enhancement-mode InA1As/InGaAs/InP high electron mobility transistors(E-HEMTs).By introducing lattice mismatched strained aluminum-rich In_(0.45) Al_(0.55)As as the Schottky contact material to enhance the barrier height,we have developed InP-based InAlAs/InGaAs/InP E-HEMT with threshold voltage of about 150 m V.A maximum extrinsic transconductance of 660mS/mm and output conductance of 15mS/mm are measured for 1μm-gate length devices at room temperature.The devices also show excellent radio-frequency performance with cutoff frequency of 50 GHz and maximum oscillation frequency of 54 GHz.
文摘A functional field effect transistor with self-organized In_(0.15)Ga_(0.85)As/GaAs quantum wires(QWRs)as a channel was achieved by molecular beam epitaxy on a(553)B GaAs substrate.Both the three-dimensional image of atom force microscopy and the polarization of the photoluminance peaks reveal that the channel of the device is a self-organized QWR structure.The device with a gate-length of 2μm and a source-drain spacing of 5μm performed a good enhancement-mode characteristic and a maximum transconductance of 65 mS/mm was obtained at the gate voltage of 1.0 V by the geometric gate-width at room temperature.The saturated drain current is as high as 5.6 mA.The device exhibited a much larger current capacity due to the high density of the self-organized QWRs in its channel layer.In addition,the effective gate width was discussed in comparison with the geometric gate width of the device,from which a larger maximum transconductance of 130 mS/mm could be estimated.
基金Supported by the National Natural Science Foundation of China under Grant Nos.69976012,69896260 and 69937019Jilin Province Science Fund for Young Research No.19990529-2.and 863 Plan with No.863-307-15-3(08).
文摘Room temperature photoluminescence(PL)spectra of InAs self-assembled quantum dots(QDs)deposited on a GaAs/InP and InP substrate are investigated.From the PL spectra,we find that the peak position of InAs QDs appears red-shift from 0.795 to 0.785 eV after we insert a thin tensile GaAs layer between InAs QD layer and InP buffer layer.In order to explain this phenomenon in theory,we examine the strain tensor in InAs quantum dots by using a valence force field model and use a five-band k.p formalism to obtain the electronic structure.The calculated results show that the ground transition energy decreases from 0.789 to 0.780 eV when the thin GaAs layer is inserted.Therefore,the PL peak position should appear red-shift as shown in the experiment.
