科研成果

2015

Zhang C, Wang M, Xie B, Wen CP, Wang J, Hao Y, Wu W, Chen KJ, Shen B. Temperature Dependence of the Surface- and Buffer-Induced Current Collapse in GaN High-Electron Mobility Transistors on Si Substrate. IEEE TRANSACTIONS ON ELECTRON DEVICES. 2015;62:2475-2480.Abstract

The temperature dependence of current collapse (CC) in AlGaN/GaN high-electron mobility transistors on silicon substrate is studied in this paper. Devices without and with Si3N4 passivation are used to investigate the behavior of surface- and buffer-induced CC, respectively. It is found that the degree of surface-induced CC in unpassivated devices has a weak temperature dependence, which is induced by the cancelling out between enhanced carrier injection based on surface hopping and enhanced emission when the temperature is increased. On the other hand, the degree of buffer-induced CC in the Si3N4 passivated devices is reduced at higher temperature since the energy of hot electrons is reduced due to the phonon scattering and the trapping of hot electrons in the buffer is mitigated. Temperature-dependent transient measurement is also carried out to investigate the recovery process for these two type of CC. Two types of trap levels are identified in the unpassivated and Si3N4 passivated devices, respectively. The trap level E1 with an activation energy of 0.08 eV is supposed to be related to the surface trapping, while E2 with an activation energy of 0.22 eV is located in the buffer layer.

Cheng Z, Xu Z, Xu S, Wang X. Temperature dependent behavior of thermal conductivity of sub-5 nm Ir film: Defect-electron scattering quantified by residual thermal resistivity. Journal of Applied Physics. 2015;117(2):024307.

Cheng Z. Temperature-dependent thermal and electrical conduction in metallic nanostructures. 2015.

Tang H-H, Liu* P-K. Terahertz far-field super-resolution imaging through spoof surface plasmons illumination. Optics Letters. 2015;40(23):5822-5825.

Tang H-H, Liu* P-K. Terahertz metalenses for evanescent wave focusing and super- resolution imaging. Journal of Electromagnetic Waves and Applications. 2015;29(13):1776-1784.

Shao L, Stairs I, others. Testing Gravity with Pulsars in the SKA Era. In: PoS. Vol. AASKA14. ; 2015. pp. 042.

Du C-H, Lee H, Qi X-B, Liu* P-K, Chang* T-H. Theoretical study of a fourth-harmonic 400-GHz gyrotron backward-wave oscillator. IEEE Transactions on Electron Devices. 2015;62(1):207-212.

Du C-H, Lee H, Qi X-B, Liu* P-K, Chang* T-H. Theoretical study of a fourth-harmonic 400-GHz gyrotron backward-wave oscillator. IEEE Transactions on Electron Devices [Internet]. 2015;62(1):207-212. 访问链接 Abstract

The requirement of strong magnetic field is one of the major difficulties for terahertz gyrotrons. A plausible solution is to operate at higher cyclotron harmonic denoted as s, in which the magnetic field strength is reduced to 1/s of the value for the fundamental harmonic operation. This paper presents a systematic theoretical investigation of a fourth-harmonic 400-GHz gyrotron backward-wave oscillator with relatively high efficiency. An axis-encircling electron beam is employed to suppress the mode competition. The operating mode is the TE41 mode. The efficiency and bandwidth are optimized for the magnetic field tuning. Simulations suggest that the fourth-harmonic circuit is capable of achieving highest interaction efficiency ~6.5%, and tunable bandwidth 2.8 GHz at 400 GHz. The weak beam-wave coupling and serious Ohm loss on the circuit wall limit the overall performance.

Chen J, Bao Y, She Z-S. A theory for optimal heat transfer in a partitioned convection cell, in 68th Annual Meeting of the APS Division of Fluid Dynamics.Vol 60. Boston, Massachusetts; 2015:00003.

Li Y, West D, Huang H, Li J, Zhang SB, Duan W. Theory of the Dirac half metal and quantum anomalous Hall effect in Mn-intercalated epitaxial graphene. Physical Review B. 2015;92:201403.

Liu J, Xu Z, Cheng Z, Xu S, Wang X. Thermal conductivity of ultrahigh molecular weight polyethylene crystal: defect effect uncovered by 0 K limit phonon diffusion. ACS Applied Materials & Interfaces. 2015;7(49):27279-27288.

Liu J, Xu Z, Cheng Z, Xu S, Wang X. Thermal conductivity of ultrahigh molecular weight polyethylene crystal: defect effect uncovered by 0 K limit phonon diffusion. ACS applied materials & interfaces. 2015;7(49):27279-27288.

Zhang F, Liu J, Yang W, Logan BE. A thermally regenerative ammonia-based battery for efficient harvesting of low-grade thermal energy as electrical power. Energy & Environmental Science. 2015;8(1):343-349.

Wang FQ, Zhang S, Yu J, Wang Q. Thermoelectric properties of single-layered SnSe sheet. Nanoscale. 2015;7(38):15962-15970.

Zhao C, Ma S, Gao W. Thousand to one: An image compression system via cloud search, in 17th IEEE International Workshop on Multimedia Signal Processing, MMSP 2015, Xiamen, China, October 19-21, 2015.; 2015:1–5. 访问链接

Chen X, Zeng Z, Wang H, Xi P. Three-dimensional multimodal sub-diffraction imaging with spinning-disk confocal microscopy using blinking/fluctuating probes. Nano Research. 2015;8:2251-2260.

Zhu FY, Wang C, Zhang X, Zhao X, Zhang H. A three-step model of black silicon formation in deep reactive ion etching process. Micro Electro Mechanical Systems (MEMS), 2015 28th IEEE International Conference on. 2015:365-368.

Huang H, Wang Z, Luo N, Liu Z, Lü R, Wu J, Duan W. Time-reversal symmetry protected chiral interface states between quantum spin and quantum anomalous Hall insulators. Physical Review B. 2015;92:075138.

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