Jie Zhu - Profile on Academia.edu (original) (raw)
Papers by Jie Zhu
Crystals
In the current study, the effects of cracks in source field plates (SFPs) on the electrical perfo... more In the current study, the effects of cracks in source field plates (SFPs) on the electrical performance of AlGaN/GaN high electron mobility transistors (HEMTs) are investigated systematically using numerical simulation. In detail, the influence of crack width and junction angle in SFPs on device performance is studied. The results indicate that the SFP structure increases the breakdown voltage of a device, but the occurrence of cracks causes premature breakdown, which is confirmed experimentally by the structural analysis of these devices after breakdown. With an increase in crack width, the electrical performance becomes worse. A beveled SFP architecture is proposed by increasing the angle at the SFP junction to reduce the probability of cracking and enhance the reliability of the device. However, with an increase in bevel angle, the modulation effect of the SFP on the channel electric field is gradually weakened. Therefore, it is necessary to balance the relationship between elect...
Applied Physics Letters, 2022
Paper published as part of the special topic on Wide-and Ultrawide-Bandgap Electronic Semiconduct... more Paper published as part of the special topic on Wide-and Ultrawide-Bandgap Electronic Semiconductor Devices ARTICLES YOU MAY BE INTERESTED IN
Interface and border trapping effects in normally-off Al2O3/AlGaN/GaN MOS-HEMTs with different post-etch surface treatments
Chinese Physics B, 2020
Trapping effect in normally-off Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mob... more Trapping effect in normally-off Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mobility transistors (MOS-HEMTs) with post-etch surface treatment was studied in this paper. Diffusion-controlled interface oxidation treatment and wet etch process were adopted to improve the interface quality of MOS-HEMTs. With capacitance–voltage (C–V) measurement, the density of interface and border traps were calculated to be 1.13 × 1012 cm−2 and 6.35 × 1012 cm−2, effectively reduced by 27% and 14% compared to controlled devices, respectively. Furthermore, the state density distribution of border traps with large activation energy was analyzed using photo-assisted C–V measurement. It is found that irradiation of monochromatic light results in negative shift of C–V curves, which indicates the electron emission process from border traps. The experimental results reveals that the major border traps have an activation energy about 3.29 eV and the change of post-etch surface treatment proce...
Trap analysis of the composite 2D-3D channel in AlGaN/GaN/graded-AlGaN: Si/GaN: C multi-heterostructure at different temperature
Chinese Physics B, 2020
The graded AlGaN:Si back barrier can form the majority of three-dimensional electron gases (3DEGs... more The graded AlGaN:Si back barrier can form the majority of three-dimensional electron gases (3DEGs) at the GaN/graded AlGaN:Si heterostructure and create a composite two-dimensional (2D)–three-dimensional (3D) channel in AlGaN/GaN/graded-AlGaN:Si/GaN:C heterostructure (DH:Si/C). Frequency-dependent capacitances and conductance are measured to investigate the characteristics of the multi-temperature trap states of in DH:Si/C and AlGaN/GaN/GaN:C heterostructure (SH:C). There are fast, medium, and slow trap states in DH:Si/C, while only medium trap states exist in SH:C. The time constant/trap density for medium trap state in SH:C heterostructure are (11 μs–17.7 μs)/(1.1 × 1013 cm−2·eV−1–3.9× 1013 cm−2·eV−1) and (8.7 μs–14.1 μs)/(0.7× 1013 cm−2·eV−1–1.9× 1013 cm−2·eV−1) at 300 K and 500 K respectively. The time constant/trap density for fast, medium, and slow trap states in DH:Si/C heterostructure are (4.2 μs–7.7 μs)/(1.5× 1013 cm−2·eV−1–3.2× 1013 cm−2·eV−1), (6.8 μs–11.8 μs)/(0.8× 1013 ...
Negative bias-induced threshold voltage instability and zener/interface trapping mechanism in GaN-based MIS-HEMTs
Chinese Physics B, 2020
We investigate the instability of threshold voltage in D-mode MIS-HEMT with in-situ SiN as gate d... more We investigate the instability of threshold voltage in D-mode MIS-HEMT with in-situ SiN as gate dielectric under different negative gate stresses. The complex non-monotonic evolution of threshold voltage under the negative stress and during the recovery process is induced by the combination effect of two mechanisms. The effect of trapping behavior of interface state at SiN/AlGaN interface and the effect of zener traps in AlGaN barrier layer on the threshold voltage instability are opposite to each other. The threshold voltage shifts negatively under the negative stress due to the detrapping of the electrons at SiN/AlGaN interface, and shifts positively due to zener trapping in AlGaN barrier layer. As the stress is removed, the threshold voltage shifts positively for the retrapping of interface states and negatively for the thermal detrapping in AlGaN. However, it is the trapping behavior in the AlGaN rather than the interface state that results in the change of transconductance in t...
Method of evaluating interface traps in Al2O3/AlGaN/GaN high electron mobility transistors*
Chinese Physics B, 2019
In this paper, the interface states of the AlGaN/GaN metal–insulator–semiconductor (MIS) high ele... more In this paper, the interface states of the AlGaN/GaN metal–insulator–semiconductor (MIS) high electron mobility transistors (HEMTs) with an Al2O3 gate dielectric are systematically evaluated. By frequency-dependent capacitance and conductance measurements, trap density and time constant at Al2O3/AlGaN and AlGaN/GaN interface are determined. The experimental results reveal that the density of trap states and the activation energy at the Al2O3/AlGaN interface are much higher than at the AlGaN/GaN interface. The photo-assisted capacitance-voltage measurements are performed to characterize the deep-level traps located near mid-gap at the Al2O3/AlGaN interface, which indicates that a density of deep-level traps is lower than the density of the shallow-level states.
Physica A: Statistical Mechanics and its Applications, 2019
We study the model of an electron in an isotropic quantum dot in the presence of a perpendicular ... more We study the model of an electron in an isotropic quantum dot in the presence of a perpendicular magnetic field and dissipation. Starting from the system plus bath approach, the quantum Langevin equations are first obtained and consequently the equation of motion. Then the effective Hamiltonian is derived from the equation of motion. We obtained a new effective Hamiltonian for the case when the magnetic field and dissipation are both present. This effective Hamiltonian is quite different from the one used widely for timedependent harmonic oscillators under a magnetic field in earlier studies. The corresponding propagator for this new effective Hamiltonian is also calculated. As an example of application, the dissipative dynamics of a Gaussian wavepacket confined in small quantum dots in the presence of a perpendicular magnetic field is studied.
Applied Physics Letters, 2017
High-frequency enhancement-mode (E-mode) AlGaN/GaN high-electron-mobility transistors (HEMTs) wit... more High-frequency enhancement-mode (E-mode) AlGaN/GaN high-electron-mobility transistors (HEMTs) with plasma oxidation technology (POT) were fabricated through plasma-enhanced chemical vapor deposition. POT enables the formation of a thin oxide layer in the gate region, which decreases the gate leakage by at least two orders of magnitude compared with conventional recessed gate HEMTs. Ultra-low leakage was achieved in the fabricated device, with I off ¼ 9.5 Â 10 À7 mA/ mm and a high ON/OFF ratio of over 10 9. Good suppression of current collapse was obtained after the application of POT in the access region. The enhancement-mode AlGaN/GaN HEMTs with POT showed an outstanding performance, with a V th of 0.4 V, a maximum drain current of 965 mA/mm, and an f max of 272 GHz.
Neurobiology of Disease, 2019
Naturally occurring autoantibodies against α-synuclein rescues memory and motor deficits and atte... more Naturally occurring autoantibodies against α-synuclein rescues memory and motor deficits and attenuates α-synuclein pathology in mouse model of Parkinson's disease. Ynbdi (2018),
Applied Physics Letters, 2017
This paper presents a systematic study on the interface traps in AlGaN/GaN metal-insulatorsemicon... more This paper presents a systematic study on the interface traps in AlGaN/GaN metal-insulatorsemiconductor (MIS) heterostructures with an atomic layer deposited Al 2 O 3 /AlN gate stack. The interface trap density in MIS heterostructures with and without recess gate is estimated to be 2.76 Â 10 13 eV À1 cm À2 and 2.38 Â 10 13 eV À1 cm À2 , respectively, by using the conductance method. The capture cross section, extracted from Arrhenius fitting, shows an exponential increase from 1.73 Â 10 À18 cm 2 to 1.07 Â 10 À16 cm 2 with an increase in trap activation energy from 0.21 eV to 0.47 eV for MIS heterostructures with recess gate, while the exponentially related capture cross section and activation energy for the case without recess gate are 1.19 Â 10 À18-2.36 Â 10 À12 cm 2 and 0.15-0.82 eV, respectively. The voltage-dependent measurement enables different interface traps detectable which are continuously distributed within the bandgap, and the exponential dependence of the capture cross section on activation energy is attributed to the entropy change accompanying electron emission from interface traps to the conduction band. The comparison between devices with and without recess gate shows that recess etching leads to a decrease in the linear dependence factor of activation energy on gate voltage from 0.61 to 0.52 and also slightly reduces the influence of atomic vibration on electron emission.
Comparative study on nitridation and oxidation plasma interface treatment for AlGaN/GaN MIS-HEMTs with AlN gate dielectric
Materials Research Express, 2017
This paper demonstrated the comparative study on interface engineering of AlN/AlGaN/GaN metal–ins... more This paper demonstrated the comparative study on interface engineering of AlN/AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) by using plasma interface pre-treatment in various ambient gases. The 15 nm AlN gate dielectric grown by plasma-enhanced atomic layer deposition significantly suppressed the gate leakage current by about two orders of magnitude and increased the peak field-effect mobility by more than 50%. NH3/N2 nitridation plasma treatment (NPT) was used to remove the 3 nm poor-quality interfacial oxide layer and N2O/N2 oxidation plasma treatment (OPT) to improve the quality of interfacial layer, both resulting in improved dielectric/barrier interface quality, positive threshold voltage (V th) shift larger than 0.9 V, and negligible dispersion. In comparison, however, NPT led to further decrease in interface charges by 3.38 × 1012 cm−2 and an extra positive V th shift of 1.3 V. Analysis with fat field-effect transistors showed that NPT resulted in better sub-threshold characteristics and transconductance linearity for MIS-HEMTs compared with OPT. The comparative study suggested that direct removing the poor interfacial oxide layer by nitridation plasma was superior to improving the quality of interfacial layer by oxidation plasma for the interface engineering of GaN-based MIS-HEMTs.
Influence of surface states on deep level transient spectroscopy in AlGaN/GaN heterostructure
Chinese Physics B, 2016
Deep level transient spectroscopy (DLTS) as a method to investigate deep traps in AlGaN/GaN heter... more Deep level transient spectroscopy (DLTS) as a method to investigate deep traps in AlGaN/GaN heterostructure or high electron mobility transistors (HEMTs) has been widely utilized. The DLTS measurements under different bias conditions are carried out in this paper. Two hole-like traps with active energies of E v + 0.47 eV, and E v + 0.10 eV are observed, which are related to surface states. The electron traps with active energies of E c − 0.56 eV are located in the channel, those with E c − 0.33 eV and E c − 0.88 eV are located in the AlGaN layer. The presence of surface states has a strong influence on the detection of electron traps, especially when the electron traps are low in density. The DLTS signal peak height of the electron trap is reduced and even disappears due to the presence of plentiful surface state.
Investigation of trap states in Al 2 O 3 InAlN/GaN metal–oxide–semiconductor high-electron-mobility transistors
Chinese Physics B, 2015
In this paper the trapping effects in Al2O3/In0.17Al0.83N/GaN MOS-HEMT (here, HEMT stands for hig... more In this paper the trapping effects in Al2O3/In0.17Al0.83N/GaN MOS-HEMT (here, HEMT stands for high electron mobility transistor) are investigated by frequency-dependent capacitance and conductance analysis. The trap states are found at both the Al2O3/InAlN and InAlN/GaN interface. Trap states in InAlN/GaN heterostructure are determined to have mixed de-trapping mechanisms, emission, and tunneling. Part of the electrons captured in the trap states are likely to tunnel into the two-dimensional electron gas (2DEG) channel under serious band bending and stronger electric field peak caused by high Al content in the InAlN barrier, which explains the opposite voltage dependence of time constant and relation between the time constant and energy of the trap states.
Oncotarget, Jan 26, 2017
Increasing evidences showed that long non-coding RNAs (lncRNAs) play vital roles in tumor progres... more Increasing evidences showed that long non-coding RNAs (lncRNAs) play vital roles in tumor progression. Recent studies indicated that lncRNA TUG1 was upregulated and promoted tumor processes in several cancers. However, the expression and underlying mechanism of TUG1 in cervical cancer remain unclear. In the present study, we found that TUG1 expression was upregulated in cervical cancer tissues and correlated with advanced clinical features and poor overall survival. TUG1 knockdown suppressed cervical cancer cell growth and metastasis in vitro and tumor growth in vivo. In addition, our results indicated that TUG1 could act as an endogenous sponge by directly binding to miR-138-5p and suppressed miR-138-5p expression. Furthermore, we found that TUG1 could reverse the inhibitory effect of miR-138-5p on cervical cancer cells processes, which might be involved in the activation of SIRT1, a target gene of miR-138-5p, and activation of Wnt/β-catenin signaling pathway. Taken together, we el...
Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility transistors under reverse-bias stress
Applied Physics Letters, 2014
ABSTRACT Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility ... more ABSTRACT Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility transistors are investigated. The gate leakage current decreases significantly upon removing the SiN layer and no clear critical voltage for the sudden degradation of the gate leakage current can be observed in the reverse-bias step-stress experiments. Gate-lag measurements reveal the decrease of the fast-state surface traps and the increase of slow-state traps after the passivation layer removal. It is postulated that consistent surface charging relieves the electric field peak on the gate edge, thus the inverse piezoelectric effect is shielded.
We show how to construct covariant amplitudes for processes involving higher spins in this paper.... more We show how to construct covariant amplitudes for processes involving higher spins in this paper. First we give the explicit expressions of Rarita-Schwinger wave functions and propagators for bosons with spins, then kinematic singularity free 3-leg effective vertexes are derived and given in a list. Equivalence relations are worked out to get these independent vertexes. Constraints of space reflection symmetry and boson symmetry are considered and shown in a explicit way. Some helicity amplitudes for two-body decays in center of frame are calculated. Finally the covariant helicity amplitudes for the process a1 → π + π + π − are constructed to illustrate how to include background (1PI) amplitudes. Both background amplitudes and resonance amplitudes are needed to give reliable descriptions to high energy reactions.
We derive the explicit expressions of the canonical and helicity wave functions for massive parti... more We derive the explicit expressions of the canonical and helicity wave functions for massive particles with arbitrary spins. Properties of these wave functions are discussed.
We propose to search for CP-violating effects in the decay ψ(2S) → J/ψππ. The scheme has the adva... more We propose to search for CP-violating effects in the decay ψ(2S) → J/ψππ. The scheme has the advantage that one does not need to track two or more CP-conjugate processes. Model independent amplitudes are derived for this purpose. The fact that leading CP violating terms are O(k) under low energy expansion and the processes are flavor disconnected make the measurement of these CP breaking parameters practical. Our results can be extended to the case of Υ(2S) → Υ(1S)ππ and Υ(3S) → Υ(2S)ππ straightforwardly.
Physical Review D, 2008
In this work, we consider the canonical charmonium assignments for Y(4360) and Y(4660). Y(4660) i... more In this work, we consider the canonical charmonium assignments for Y(4360) and Y(4660). Y(4660) is good candidate of 5 3 S 1 cc state, the possibility of Y(4360) as a 3 3 D 1 cc state is studied, and the charmonium hybrid interpretation of Y(4360) can not be excluded completely. We evaluate the e + e − leptonic widths, E1 transitions, M1 transitions and the open flavor strong decays of Y(4360) and Y(4660). Experimental tests for the charmonium assignments are suggested.
Research in Astronomy and Astrophysics, 2012
We present the Data Release 4&5 quasar catalog from the quasar survey by Large Sky Area Multi-Obj... more We present the Data Release 4&5 quasar catalog from the quasar survey by Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), which includes quasars observed between September 2015 and June 2017. There are a total of 19,253 quasars identified by visual inspections of the spectra. Among them, 11,458 are independently discovered by LAMOST, in which 3296 were reported by SDSS DR12 and DR14 quasar catalog after our survey began, while the rest 8162 are new discoveries of LAMOST. We provide the emission line measurements for the Hα, Hβ, Mg II and/or C IV for 18100 quasars. Since LAMOST does not have absolute flux calibration information, we obtain the monochromatic continuum luminosities by fitting the SDSS photometric data using the quasar spectra, and then estimate the black hole masses. The catalog and spectra for these quasars are available online. This is the third installment in the series of LAMOST quasar survey which has released spectra for totally ∼ 43, 000 quasars hitherto. There are 24,772 independently discovered quasars, 17,128 of which are newly discovered. In addition to the great supplement to the new quasar discoveries, LAMOST has also provided a large database (overlapped with SDSS) for investigating the quasar spectral variability and discovering unusual quasars, including changing-look quasars, with ongoing and upcoming large surveys.
Crystals
In the current study, the effects of cracks in source field plates (SFPs) on the electrical perfo... more In the current study, the effects of cracks in source field plates (SFPs) on the electrical performance of AlGaN/GaN high electron mobility transistors (HEMTs) are investigated systematically using numerical simulation. In detail, the influence of crack width and junction angle in SFPs on device performance is studied. The results indicate that the SFP structure increases the breakdown voltage of a device, but the occurrence of cracks causes premature breakdown, which is confirmed experimentally by the structural analysis of these devices after breakdown. With an increase in crack width, the electrical performance becomes worse. A beveled SFP architecture is proposed by increasing the angle at the SFP junction to reduce the probability of cracking and enhance the reliability of the device. However, with an increase in bevel angle, the modulation effect of the SFP on the channel electric field is gradually weakened. Therefore, it is necessary to balance the relationship between elect...
Applied Physics Letters, 2022
Paper published as part of the special topic on Wide-and Ultrawide-Bandgap Electronic Semiconduct... more Paper published as part of the special topic on Wide-and Ultrawide-Bandgap Electronic Semiconductor Devices ARTICLES YOU MAY BE INTERESTED IN
Interface and border trapping effects in normally-off Al2O3/AlGaN/GaN MOS-HEMTs with different post-etch surface treatments
Chinese Physics B, 2020
Trapping effect in normally-off Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mob... more Trapping effect in normally-off Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mobility transistors (MOS-HEMTs) with post-etch surface treatment was studied in this paper. Diffusion-controlled interface oxidation treatment and wet etch process were adopted to improve the interface quality of MOS-HEMTs. With capacitance–voltage (C–V) measurement, the density of interface and border traps were calculated to be 1.13 × 1012 cm−2 and 6.35 × 1012 cm−2, effectively reduced by 27% and 14% compared to controlled devices, respectively. Furthermore, the state density distribution of border traps with large activation energy was analyzed using photo-assisted C–V measurement. It is found that irradiation of monochromatic light results in negative shift of C–V curves, which indicates the electron emission process from border traps. The experimental results reveals that the major border traps have an activation energy about 3.29 eV and the change of post-etch surface treatment proce...
Trap analysis of the composite 2D-3D channel in AlGaN/GaN/graded-AlGaN: Si/GaN: C multi-heterostructure at different temperature
Chinese Physics B, 2020
The graded AlGaN:Si back barrier can form the majority of three-dimensional electron gases (3DEGs... more The graded AlGaN:Si back barrier can form the majority of three-dimensional electron gases (3DEGs) at the GaN/graded AlGaN:Si heterostructure and create a composite two-dimensional (2D)–three-dimensional (3D) channel in AlGaN/GaN/graded-AlGaN:Si/GaN:C heterostructure (DH:Si/C). Frequency-dependent capacitances and conductance are measured to investigate the characteristics of the multi-temperature trap states of in DH:Si/C and AlGaN/GaN/GaN:C heterostructure (SH:C). There are fast, medium, and slow trap states in DH:Si/C, while only medium trap states exist in SH:C. The time constant/trap density for medium trap state in SH:C heterostructure are (11 μs–17.7 μs)/(1.1 × 1013 cm−2·eV−1–3.9× 1013 cm−2·eV−1) and (8.7 μs–14.1 μs)/(0.7× 1013 cm−2·eV−1–1.9× 1013 cm−2·eV−1) at 300 K and 500 K respectively. The time constant/trap density for fast, medium, and slow trap states in DH:Si/C heterostructure are (4.2 μs–7.7 μs)/(1.5× 1013 cm−2·eV−1–3.2× 1013 cm−2·eV−1), (6.8 μs–11.8 μs)/(0.8× 1013 ...
Negative bias-induced threshold voltage instability and zener/interface trapping mechanism in GaN-based MIS-HEMTs
Chinese Physics B, 2020
We investigate the instability of threshold voltage in D-mode MIS-HEMT with in-situ SiN as gate d... more We investigate the instability of threshold voltage in D-mode MIS-HEMT with in-situ SiN as gate dielectric under different negative gate stresses. The complex non-monotonic evolution of threshold voltage under the negative stress and during the recovery process is induced by the combination effect of two mechanisms. The effect of trapping behavior of interface state at SiN/AlGaN interface and the effect of zener traps in AlGaN barrier layer on the threshold voltage instability are opposite to each other. The threshold voltage shifts negatively under the negative stress due to the detrapping of the electrons at SiN/AlGaN interface, and shifts positively due to zener trapping in AlGaN barrier layer. As the stress is removed, the threshold voltage shifts positively for the retrapping of interface states and negatively for the thermal detrapping in AlGaN. However, it is the trapping behavior in the AlGaN rather than the interface state that results in the change of transconductance in t...
Method of evaluating interface traps in Al2O3/AlGaN/GaN high electron mobility transistors*
Chinese Physics B, 2019
In this paper, the interface states of the AlGaN/GaN metal–insulator–semiconductor (MIS) high ele... more In this paper, the interface states of the AlGaN/GaN metal–insulator–semiconductor (MIS) high electron mobility transistors (HEMTs) with an Al2O3 gate dielectric are systematically evaluated. By frequency-dependent capacitance and conductance measurements, trap density and time constant at Al2O3/AlGaN and AlGaN/GaN interface are determined. The experimental results reveal that the density of trap states and the activation energy at the Al2O3/AlGaN interface are much higher than at the AlGaN/GaN interface. The photo-assisted capacitance-voltage measurements are performed to characterize the deep-level traps located near mid-gap at the Al2O3/AlGaN interface, which indicates that a density of deep-level traps is lower than the density of the shallow-level states.
Physica A: Statistical Mechanics and its Applications, 2019
We study the model of an electron in an isotropic quantum dot in the presence of a perpendicular ... more We study the model of an electron in an isotropic quantum dot in the presence of a perpendicular magnetic field and dissipation. Starting from the system plus bath approach, the quantum Langevin equations are first obtained and consequently the equation of motion. Then the effective Hamiltonian is derived from the equation of motion. We obtained a new effective Hamiltonian for the case when the magnetic field and dissipation are both present. This effective Hamiltonian is quite different from the one used widely for timedependent harmonic oscillators under a magnetic field in earlier studies. The corresponding propagator for this new effective Hamiltonian is also calculated. As an example of application, the dissipative dynamics of a Gaussian wavepacket confined in small quantum dots in the presence of a perpendicular magnetic field is studied.
Applied Physics Letters, 2017
High-frequency enhancement-mode (E-mode) AlGaN/GaN high-electron-mobility transistors (HEMTs) wit... more High-frequency enhancement-mode (E-mode) AlGaN/GaN high-electron-mobility transistors (HEMTs) with plasma oxidation technology (POT) were fabricated through plasma-enhanced chemical vapor deposition. POT enables the formation of a thin oxide layer in the gate region, which decreases the gate leakage by at least two orders of magnitude compared with conventional recessed gate HEMTs. Ultra-low leakage was achieved in the fabricated device, with I off ¼ 9.5 Â 10 À7 mA/ mm and a high ON/OFF ratio of over 10 9. Good suppression of current collapse was obtained after the application of POT in the access region. The enhancement-mode AlGaN/GaN HEMTs with POT showed an outstanding performance, with a V th of 0.4 V, a maximum drain current of 965 mA/mm, and an f max of 272 GHz.
Neurobiology of Disease, 2019
Naturally occurring autoantibodies against α-synuclein rescues memory and motor deficits and atte... more Naturally occurring autoantibodies against α-synuclein rescues memory and motor deficits and attenuates α-synuclein pathology in mouse model of Parkinson's disease. Ynbdi (2018),
Applied Physics Letters, 2017
This paper presents a systematic study on the interface traps in AlGaN/GaN metal-insulatorsemicon... more This paper presents a systematic study on the interface traps in AlGaN/GaN metal-insulatorsemiconductor (MIS) heterostructures with an atomic layer deposited Al 2 O 3 /AlN gate stack. The interface trap density in MIS heterostructures with and without recess gate is estimated to be 2.76 Â 10 13 eV À1 cm À2 and 2.38 Â 10 13 eV À1 cm À2 , respectively, by using the conductance method. The capture cross section, extracted from Arrhenius fitting, shows an exponential increase from 1.73 Â 10 À18 cm 2 to 1.07 Â 10 À16 cm 2 with an increase in trap activation energy from 0.21 eV to 0.47 eV for MIS heterostructures with recess gate, while the exponentially related capture cross section and activation energy for the case without recess gate are 1.19 Â 10 À18-2.36 Â 10 À12 cm 2 and 0.15-0.82 eV, respectively. The voltage-dependent measurement enables different interface traps detectable which are continuously distributed within the bandgap, and the exponential dependence of the capture cross section on activation energy is attributed to the entropy change accompanying electron emission from interface traps to the conduction band. The comparison between devices with and without recess gate shows that recess etching leads to a decrease in the linear dependence factor of activation energy on gate voltage from 0.61 to 0.52 and also slightly reduces the influence of atomic vibration on electron emission.
Comparative study on nitridation and oxidation plasma interface treatment for AlGaN/GaN MIS-HEMTs with AlN gate dielectric
Materials Research Express, 2017
This paper demonstrated the comparative study on interface engineering of AlN/AlGaN/GaN metal–ins... more This paper demonstrated the comparative study on interface engineering of AlN/AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) by using plasma interface pre-treatment in various ambient gases. The 15 nm AlN gate dielectric grown by plasma-enhanced atomic layer deposition significantly suppressed the gate leakage current by about two orders of magnitude and increased the peak field-effect mobility by more than 50%. NH3/N2 nitridation plasma treatment (NPT) was used to remove the 3 nm poor-quality interfacial oxide layer and N2O/N2 oxidation plasma treatment (OPT) to improve the quality of interfacial layer, both resulting in improved dielectric/barrier interface quality, positive threshold voltage (V th) shift larger than 0.9 V, and negligible dispersion. In comparison, however, NPT led to further decrease in interface charges by 3.38 × 1012 cm−2 and an extra positive V th shift of 1.3 V. Analysis with fat field-effect transistors showed that NPT resulted in better sub-threshold characteristics and transconductance linearity for MIS-HEMTs compared with OPT. The comparative study suggested that direct removing the poor interfacial oxide layer by nitridation plasma was superior to improving the quality of interfacial layer by oxidation plasma for the interface engineering of GaN-based MIS-HEMTs.
Influence of surface states on deep level transient spectroscopy in AlGaN/GaN heterostructure
Chinese Physics B, 2016
Deep level transient spectroscopy (DLTS) as a method to investigate deep traps in AlGaN/GaN heter... more Deep level transient spectroscopy (DLTS) as a method to investigate deep traps in AlGaN/GaN heterostructure or high electron mobility transistors (HEMTs) has been widely utilized. The DLTS measurements under different bias conditions are carried out in this paper. Two hole-like traps with active energies of E v + 0.47 eV, and E v + 0.10 eV are observed, which are related to surface states. The electron traps with active energies of E c − 0.56 eV are located in the channel, those with E c − 0.33 eV and E c − 0.88 eV are located in the AlGaN layer. The presence of surface states has a strong influence on the detection of electron traps, especially when the electron traps are low in density. The DLTS signal peak height of the electron trap is reduced and even disappears due to the presence of plentiful surface state.
Investigation of trap states in Al 2 O 3 InAlN/GaN metal–oxide–semiconductor high-electron-mobility transistors
Chinese Physics B, 2015
In this paper the trapping effects in Al2O3/In0.17Al0.83N/GaN MOS-HEMT (here, HEMT stands for hig... more In this paper the trapping effects in Al2O3/In0.17Al0.83N/GaN MOS-HEMT (here, HEMT stands for high electron mobility transistor) are investigated by frequency-dependent capacitance and conductance analysis. The trap states are found at both the Al2O3/InAlN and InAlN/GaN interface. Trap states in InAlN/GaN heterostructure are determined to have mixed de-trapping mechanisms, emission, and tunneling. Part of the electrons captured in the trap states are likely to tunnel into the two-dimensional electron gas (2DEG) channel under serious band bending and stronger electric field peak caused by high Al content in the InAlN barrier, which explains the opposite voltage dependence of time constant and relation between the time constant and energy of the trap states.
Oncotarget, Jan 26, 2017
Increasing evidences showed that long non-coding RNAs (lncRNAs) play vital roles in tumor progres... more Increasing evidences showed that long non-coding RNAs (lncRNAs) play vital roles in tumor progression. Recent studies indicated that lncRNA TUG1 was upregulated and promoted tumor processes in several cancers. However, the expression and underlying mechanism of TUG1 in cervical cancer remain unclear. In the present study, we found that TUG1 expression was upregulated in cervical cancer tissues and correlated with advanced clinical features and poor overall survival. TUG1 knockdown suppressed cervical cancer cell growth and metastasis in vitro and tumor growth in vivo. In addition, our results indicated that TUG1 could act as an endogenous sponge by directly binding to miR-138-5p and suppressed miR-138-5p expression. Furthermore, we found that TUG1 could reverse the inhibitory effect of miR-138-5p on cervical cancer cells processes, which might be involved in the activation of SIRT1, a target gene of miR-138-5p, and activation of Wnt/β-catenin signaling pathway. Taken together, we el...
Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility transistors under reverse-bias stress
Applied Physics Letters, 2014
ABSTRACT Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility ... more ABSTRACT Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility transistors are investigated. The gate leakage current decreases significantly upon removing the SiN layer and no clear critical voltage for the sudden degradation of the gate leakage current can be observed in the reverse-bias step-stress experiments. Gate-lag measurements reveal the decrease of the fast-state surface traps and the increase of slow-state traps after the passivation layer removal. It is postulated that consistent surface charging relieves the electric field peak on the gate edge, thus the inverse piezoelectric effect is shielded.
We show how to construct covariant amplitudes for processes involving higher spins in this paper.... more We show how to construct covariant amplitudes for processes involving higher spins in this paper. First we give the explicit expressions of Rarita-Schwinger wave functions and propagators for bosons with spins, then kinematic singularity free 3-leg effective vertexes are derived and given in a list. Equivalence relations are worked out to get these independent vertexes. Constraints of space reflection symmetry and boson symmetry are considered and shown in a explicit way. Some helicity amplitudes for two-body decays in center of frame are calculated. Finally the covariant helicity amplitudes for the process a1 → π + π + π − are constructed to illustrate how to include background (1PI) amplitudes. Both background amplitudes and resonance amplitudes are needed to give reliable descriptions to high energy reactions.
We derive the explicit expressions of the canonical and helicity wave functions for massive parti... more We derive the explicit expressions of the canonical and helicity wave functions for massive particles with arbitrary spins. Properties of these wave functions are discussed.
We propose to search for CP-violating effects in the decay ψ(2S) → J/ψππ. The scheme has the adva... more We propose to search for CP-violating effects in the decay ψ(2S) → J/ψππ. The scheme has the advantage that one does not need to track two or more CP-conjugate processes. Model independent amplitudes are derived for this purpose. The fact that leading CP violating terms are O(k) under low energy expansion and the processes are flavor disconnected make the measurement of these CP breaking parameters practical. Our results can be extended to the case of Υ(2S) → Υ(1S)ππ and Υ(3S) → Υ(2S)ππ straightforwardly.
Physical Review D, 2008
In this work, we consider the canonical charmonium assignments for Y(4360) and Y(4660). Y(4660) i... more In this work, we consider the canonical charmonium assignments for Y(4360) and Y(4660). Y(4660) is good candidate of 5 3 S 1 cc state, the possibility of Y(4360) as a 3 3 D 1 cc state is studied, and the charmonium hybrid interpretation of Y(4360) can not be excluded completely. We evaluate the e + e − leptonic widths, E1 transitions, M1 transitions and the open flavor strong decays of Y(4360) and Y(4660). Experimental tests for the charmonium assignments are suggested.
Research in Astronomy and Astrophysics, 2012
We present the Data Release 4&5 quasar catalog from the quasar survey by Large Sky Area Multi-Obj... more We present the Data Release 4&5 quasar catalog from the quasar survey by Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), which includes quasars observed between September 2015 and June 2017. There are a total of 19,253 quasars identified by visual inspections of the spectra. Among them, 11,458 are independently discovered by LAMOST, in which 3296 were reported by SDSS DR12 and DR14 quasar catalog after our survey began, while the rest 8162 are new discoveries of LAMOST. We provide the emission line measurements for the Hα, Hβ, Mg II and/or C IV for 18100 quasars. Since LAMOST does not have absolute flux calibration information, we obtain the monochromatic continuum luminosities by fitting the SDSS photometric data using the quasar spectra, and then estimate the black hole masses. The catalog and spectra for these quasars are available online. This is the third installment in the series of LAMOST quasar survey which has released spectra for totally ∼ 43, 000 quasars hitherto. There are 24,772 independently discovered quasars, 17,128 of which are newly discovered. In addition to the great supplement to the new quasar discoveries, LAMOST has also provided a large database (overlapped with SDSS) for investigating the quasar spectral variability and discovering unusual quasars, including changing-look quasars, with ongoing and upcoming large surveys.