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On the reverse leakage current of Schottky contacts on free-standing GaN at high reverse biases 下载免费PDF全文
In this work, a dislocation-related tunneling leakage current model is developed to explain the temperature-dependent reverse current–voltage(I–V –T) characteristics of a Schottky barrier diode fabricated on free-standing GaN substrate for reverse-bias voltages up to-150 V. The model suggests that the reverse leakage current is dominated by the direct tunneling of electrons from Schottky contact metal into a continuum of states associated with conductive dislocations in GaN epilayer.A reverse leakage current ideality factor, which originates from the scattering effect at metal/GaN interface, is introduced into the model. Good agreement between the experimental data and the simulated I–V curves is obtained. 相似文献
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将齿轮传动系统的齿轮轴承简化为具有集中质量的固支梁,将齿轮受到啮合齿轮的意外撞击看成是质量块对梁的冲击。给出弯扭组合的Mises屈服条件,指出传动轴受冲击时不能忽略扭矩作用。分析了弯曲和扭转作用下的结构响应,进行了应变率修正,给出特殊情况下弯扭响应的简化分析。算例表明,弯扭冲击下传动轴的横向位移和扭转角都较大,不可忽略应变率效应;传动轴直径是影响横向位移的重要因素。 相似文献
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Magnetic properties of L1_0 FePt thin film influenced by recoverable strains stemmed from the polarization of Pb(Mg_(1/3)Nb_(2/3))O_3–PbTiO_3 substrate 下载免费PDF全文
The magnetic properties and magnetization reversible processes of L1_0 FePt(3 nm)/Pb(Mg_(1/3)Nb_(2/3))O_3–PbTiO_3(PMN–PT) heterostructure were investigated by using the phase field model. The simulation results show that the magnetic coercivities and magnetic domains evolution in the L1_0 FePt thin film are significantly influenced by the compressive strains stemming from the polarization of single crystal PMN–PT substrate under an applied electric field. It is found that the magnetic coercivities increase with increasing of the compressive strain. A large compressive strain is beneficial to aligning the magnetic moments along the out-of-plane direction and to the enhancement of perpendicular magnetic anisotropy. The variations of magnetic energy densities show that when compressive strains are different at the magnetization reversible processes, the magnetic anisotropy energies and the magnetic exchange energies firstly increase and then decrease, the negative demagnetization energy peaks appear at coercivities fields, and the magnetoelastic energies are invariable at large external magnetic field with the energy maximum appearing at coercivities fields. The variations of the magnetoelastic energies bring about the perpendicular magnetic anisotropy so that the magnetoelastic energy is lower at the large external magnetic fields, whereas the appearance of magnetoelastic energy peaks is due to the magnetization-altered direction from the normal direction of the plane of the L1_0 FePt thin film at coercivities fields. 相似文献
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