The viability of the indium phosphide(InP)Gunn diode as a source for low-THz band applications is analyzed based on a notch-δ-doped structure using the Monte Carlo modeling.The presence of theδ-doped layer could enh...The viability of the indium phosphide(InP)Gunn diode as a source for low-THz band applications is analyzed based on a notch-δ-doped structure using the Monte Carlo modeling.The presence of theδ-doped layer could enhance the current harmonic amplitude(A0)and the fundamental operating frequency(f0)of the InP Gunn diode beyond 300 GHz as compared with the conventional notch-doped structure for a 600-nm length device.With its superior electron transport properties,the notch-δ-doped InP Gunn diodes outperform the corresponding gallium arsenide(GaAs)diodes with up to 1.35 times higher in f0 and 2.4 times larger in A0 under DC biases.An optimized InP notch-δ-doped structure is estimated to be capable of generating 0.32-W radio-frequency(RF)power at 361 GHz.The Monte Carlo simulations predict a reduction of 44%in RF power,when the device temperature is increased from 300 K to 500 K;however,its operating frequency lies at 280 GHz which is within the low-THz band.This shows that the notch-δ-doped InP Gunn diode is a highly promising signal source for low-THz sensors,which are in a high demand in the autonomous vehicle industry.展开更多
The low-temperature measurement of Hall effect of the two-dimensional electron system in a double-layered gated Si-δ-doped GaAs is presented.A complex peculiar nonlinear dependence of the depletion on gate voltage i...The low-temperature measurement of Hall effect of the two-dimensional electron system in a double-layered gated Si-δ-doped GaAs is presented.A complex peculiar nonlinear dependence of the depletion on gate voltage is observed.The nonlinearity is also explained on the basis of the assumption that the double-capacity model consists of two δ-doped two-dimensional electron layers and a metallic gate,and the experimental result that the electron mobility is linear with the electron density on a log-log scale.展开更多
Three samples of GaAs/A1As multiple-quantum wells with different quantum well widths and tS-doped with Be ac- ceptors at the well center were grown on （100） GaAs substrates by molecular beam epitaxy. Polarized Raman...Three samples of GaAs/A1As multiple-quantum wells with different quantum well widths and tS-doped with Be ac- ceptors at the well center were grown on （100） GaAs substrates by molecular beam epitaxy. Polarized Raman spectra were recorded on the three samples at temperatures in a range of 4-50 K in a backscattering configuration. The two branches of coupled modes due to the interaction of the hole intersubband transitions and the quantum-well longitudinal optical （LO） phonon were observed clearly. The evaluation formalism of the Green function was employed and each lineshape of the Raman spectrum of the coupled modes was simulated. The dependence of the peak position of Raman shifts of the two coupled modes as well as the quantum-well LO phonon on the quantum-well size and measured temperature were given, and the coupling interaction mechanism between the hole subband transitions and the quantum-well LO phonon was researched.展开更多
We report a far-infrared absorption study of internal transitions of shallow Be acceptors in both bulk GaAs and a series of δ-doped GaAs/AlAs multiple quantum well samples with well thicknesses of 20,15 and 10 nm. Lo...We report a far-infrared absorption study of internal transitions of shallow Be acceptors in both bulk GaAs and a series of δ-doped GaAs/AlAs multiple quantum well samples with well thicknesses of 20,15 and 10 nm. Low temperature far-infrared absorp-tion measurements clearly show three principal absorption lines due to transitions of Be-acceptor states from the ground state to the first three odd-parity excited states,respec-tively. Using a variational principle,the 2p-1s transition energies of quantum confined Be acceptors are calculated as a function of the well width. It is found that the theoretical calculation of the 2pz → 1s transitions is in good agreement with the D-like line experi-mental data.展开更多
The impurity-doping in semiconductors is the way to control their electroinc andphoto-electronic properties. The distribution and amount of the dopant affect their physi-cal properties. The development of the molecula...The impurity-doping in semiconductors is the way to control their electroinc andphoto-electronic properties. The distribution and amount of the dopant affect their physi-cal properties. The development of the molecular beam epitaxy (MBE) and other epitaxytechniques has attracted full atttention to new semiconductor materials, such assuperlattices. Recently, δ-doped semiconductors, which can reduce the scattering ofimpurity in two-dimensional electron (hole) systems, have been showing promisingpotentials for scientific researches and techmological applications.展开更多
We report photoluminescence studies of internal transitions of shallow Be acceptors in bulk GaAs and a series of S-doped GaAs/ALAs multiple quantum well samples with well width ranging from 3 to 20nm. A series of Be S...We report photoluminescence studies of internal transitions of shallow Be acceptors in bulk GaAs and a series of S-doped GaAs/ALAs multiple quantum well samples with well width ranging from 3 to 20nm. A series of Be S-doped GaAs/ AlAs multiple-quantum wells with the doping at the well center and a single epilayer of GaAs uniformly Be doped were grown by molecular beam epitaxy. The photoluminescence spectra were measured at 4,20,40, 80, and 120K, respectively. A two-hole transition of the acceptor-bound exciton from the ground state, 1S3/2 （/8）, to the first-excited state, 2S3/2 （Г6） , has been clearly observed. A variational principle is presented to obtain the 2s-1s transition energies of quantum confined Be acceptors as a function of the well width under the single-band effective mass and envelop function approximations. It is found that the acceptor transition energy increases with decreasing quantum-well width, and the experimental results agree well with the theoretical calculation.展开更多
文摘The viability of the indium phosphide(InP)Gunn diode as a source for low-THz band applications is analyzed based on a notch-δ-doped structure using the Monte Carlo modeling.The presence of theδ-doped layer could enhance the current harmonic amplitude(A0)and the fundamental operating frequency(f0)of the InP Gunn diode beyond 300 GHz as compared with the conventional notch-doped structure for a 600-nm length device.With its superior electron transport properties,the notch-δ-doped InP Gunn diodes outperform the corresponding gallium arsenide(GaAs)diodes with up to 1.35 times higher in f0 and 2.4 times larger in A0 under DC biases.An optimized InP notch-δ-doped structure is estimated to be capable of generating 0.32-W radio-frequency(RF)power at 361 GHz.The Monte Carlo simulations predict a reduction of 44%in RF power,when the device temperature is increased from 300 K to 500 K;however,its operating frequency lies at 280 GHz which is within the low-THz band.This shows that the notch-δ-doped InP Gunn diode is a highly promising signal source for low-THz sensors,which are in a high demand in the autonomous vehicle industry.
文摘The low-temperature measurement of Hall effect of the two-dimensional electron system in a double-layered gated Si-δ-doped GaAs is presented.A complex peculiar nonlinear dependence of the depletion on gate voltage is observed.The nonlinearity is also explained on the basis of the assumption that the double-capacity model consists of two δ-doped two-dimensional electron layers and a metallic gate,and the experimental result that the electron mobility is linear with the electron density on a log-log scale.
基金Project supported by Shandong Province Natural Science Foundation,China(Grant No.ZR2017MF018)the National Natural Science Foundation of China(Grant No.61675223)
文摘Three samples of GaAs/A1As multiple-quantum wells with different quantum well widths and tS-doped with Be ac- ceptors at the well center were grown on （100） GaAs substrates by molecular beam epitaxy. Polarized Raman spectra were recorded on the three samples at temperatures in a range of 4-50 K in a backscattering configuration. The two branches of coupled modes due to the interaction of the hole intersubband transitions and the quantum-well longitudinal optical （LO） phonon were observed clearly. The evaluation formalism of the Green function was employed and each lineshape of the Raman spectrum of the coupled modes was simulated. The dependence of the peak position of Raman shifts of the two coupled modes as well as the quantum-well LO phonon on the quantum-well size and measured temperature were given, and the coupling interaction mechanism between the hole subband transitions and the quantum-well LO phonon was researched.
文摘We report a far-infrared absorption study of internal transitions of shallow Be acceptors in both bulk GaAs and a series of δ-doped GaAs/AlAs multiple quantum well samples with well thicknesses of 20,15 and 10 nm. Low temperature far-infrared absorp-tion measurements clearly show three principal absorption lines due to transitions of Be-acceptor states from the ground state to the first three odd-parity excited states,respec-tively. Using a variational principle,the 2p-1s transition energies of quantum confined Be acceptors are calculated as a function of the well width. It is found that the theoretical calculation of the 2pz → 1s transitions is in good agreement with the D-like line experi-mental data.
基金Project spported partially by the major project "Applications of Experimental Synchrotron Radiation Methods" from Chinese Academy of Sciences.
文摘The impurity-doping in semiconductors is the way to control their electroinc andphoto-electronic properties. The distribution and amount of the dopant affect their physi-cal properties. The development of the molecular beam epitaxy (MBE) and other epitaxytechniques has attracted full atttention to new semiconductor materials, such assuperlattices. Recently, δ-doped semiconductors, which can reduce the scattering ofimpurity in two-dimensional electron (hole) systems, have been showing promisingpotentials for scientific researches and techmological applications.
基金the National Natural Science Foundation of China(No.60776044)the Natural Science Foundation of Shandong Province(No.2006ZRA10001)~~
文摘We report photoluminescence studies of internal transitions of shallow Be acceptors in bulk GaAs and a series of S-doped GaAs/ALAs multiple quantum well samples with well width ranging from 3 to 20nm. A series of Be S-doped GaAs/ AlAs multiple-quantum wells with the doping at the well center and a single epilayer of GaAs uniformly Be doped were grown by molecular beam epitaxy. The photoluminescence spectra were measured at 4,20,40, 80, and 120K, respectively. A two-hole transition of the acceptor-bound exciton from the ground state, 1S3/2 （/8）, to the first-excited state, 2S3/2 （Г6） , has been clearly observed. A variational principle is presented to obtain the 2s-1s transition energies of quantum confined Be acceptors as a function of the well width under the single-band effective mass and envelop function approximations. It is found that the acceptor transition energy increases with decreasing quantum-well width, and the experimental results agree well with the theoretical calculation.
