High electronic density is achieved by polarization doping without an impurity dopant in graded AIGaN films. Low specific contact resistance is studied on the polarization-doped A1GaN/GaN heterojunctions by using the ...High electronic density is achieved by polarization doping without an impurity dopant in graded AIGaN films. Low specific contact resistance is studied on the polarization-doped A1GaN/GaN heterojunctions by using the transmission line method （TLM）. The sheet density of polarization-doped A1GaN/GaN heterojunction is 6 × 10 14 cm-2 at room temperature. The linearly graded material structure is demonstrated by X-ray diffraction. The cartier concentration and mobility are characterized by a temperature-dependent Hall measurement. Multiple-layer metal （Ti/A1/Ti/Au） is deposited and annealed at 650 ℃ to realize the Ohmic contacts on the graded A1GaN/GaN heterojunctions.展开更多
We have studied the self-consistent states of nano- and micro-particle polarized powders and structures consisting of parallel particle chains and have determined conditions under which the static dielectric permittiv...We have studied the self-consistent states of nano- and micro-particle polarized powders and structures consisting of parallel particle chains and have determined conditions under which the static dielectric permittivity of a disperse system is negative. It has been shown that in such system an electric current runs without ohmic losses. We present the arguments for the physics of spontaneous emergence of the electric field in disperse systems made up of electrically neutral particles. It has been determined the influence the phase boundaries of a disperse system has on the origin of spontaneous polarization state. The structures consisting of parallel chains of dielectric particles can exhibit spontaneous polarization. In this case the properties of the spherical structure are similar to those of the ball lightning. It has been established correspondence of the obtained theoretical results with the experimental data available in the literature.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61204098 and 61371046)
文摘High electronic density is achieved by polarization doping without an impurity dopant in graded AIGaN films. Low specific contact resistance is studied on the polarization-doped A1GaN/GaN heterojunctions by using the transmission line method （TLM）. The sheet density of polarization-doped A1GaN/GaN heterojunction is 6 × 10 14 cm-2 at room temperature. The linearly graded material structure is demonstrated by X-ray diffraction. The cartier concentration and mobility are characterized by a temperature-dependent Hall measurement. Multiple-layer metal （Ti/A1/Ti/Au） is deposited and annealed at 650 ℃ to realize the Ohmic contacts on the graded A1GaN/GaN heterojunctions.
文摘We have studied the self-consistent states of nano- and micro-particle polarized powders and structures consisting of parallel particle chains and have determined conditions under which the static dielectric permittivity of a disperse system is negative. It has been shown that in such system an electric current runs without ohmic losses. We present the arguments for the physics of spontaneous emergence of the electric field in disperse systems made up of electrically neutral particles. It has been determined the influence the phase boundaries of a disperse system has on the origin of spontaneous polarization state. The structures consisting of parallel chains of dielectric particles can exhibit spontaneous polarization. In this case the properties of the spherical structure are similar to those of the ball lightning. It has been established correspondence of the obtained theoretical results with the experimental data available in the literature.
