Effects of Si δ-Doping Condition and Growth Interruption on Electrical Properties of InP-Based High Electron Mobility Transistor Structures

The InGaAs/InAIAs/InP high electron mobility transistor （HEM：F） structures with lattice-matched and pseudo- morphic channels are grown by gas source molecular beam epitaxy. Effects of Si ^-doping condition and growth interruption on the electrical properties are investigated by changing the Si-cell temperature, doping time and growth process. It is found that the optimal Si ^-doping concentration （Nd） is about 5.0 x 1012 cm-2 and the use of growth interruption has a dramatic effect on the improvement of electrical properties. The material structure and crystal interface are analyzed by secondary ion mass spectroscopy and high resolution transmission elec- tron microscopy. An InGaAs/InAiAs/InP HEMT device with a gate length of lOOnm is fabricated. The device presents good pinch-off characteristics and the kink-effect of the device is trifling. In addition, the device exhibits fT = 249 GHa and fmax 〉 400 GHz.

MECHANICAL VIBRATIONAL POWER FLOW IN BEAM-PLATE ASSEMBLIES

The vibrational power flow in the beam-plate assemblies and then with the isolators is investigated using analytical ' power flow' approach based on the some concepts of mechanical mo- bility and structural dynamics. Theoretical expressions of the power flow in the structures are given and examined. The numerical results of the expressions are good agreements with the measuring re- sults obtained by the technique of vibration intensity. On the basis of these results, possible ways of reducing the vibrational power flow in the structures are suggested .

Structural Phase Transition and a Mutation of Electron Mobility in Zn_xCd_(1-x)O Alloys

We investigate the electronic structures and phase stability of ZnO, CdO and the related alloys in rocksalt（B1）and wurzite（B4） crystal, using the first-principle density functional theory within the hybrid functional approximation. By varying the concentration of Zn components from 0% to 100%, we find that the Zn_xCd（1-x）O alloy undergoes a phase transition from octahedron to tetrahedron at x = 0.32, in agreement with the recent experimental findings. The phase transition leads to a mutation of the electron mobility originated from the changes of the effective mass. Our results qualify Zn O/Cd O alloy as an attractive candidate for photo-electrochemical and solar cell power applications.

Measures of Relative and Absolute Convergence and Pro-poor Growth with an Illustration based on China(2010–2018)

Income mobility is a key issue for understanding the process of economic growth and distributional change.Some economists have used the concept of“pro-poor growth”to examine,with individual-level panel data,whether the poor benefit more than the rich from economic growth by tracking the extent of income mobility among different population subgroups.There is also literature in macroeconomics on the measurement of convergence.This paper introduces population-weighted relative and absolute indices of mobility,convergence,and pro-poor growth;it also distinguishes between anonymous and nonanonymous approaches to these issues.The empirical analysis is based on Chinese panel data for the period 2010–2018.In both absolute and relative terms,income growth in China was greater for individuals with an initially lower income but only for lower income deciles in relative terms.There was also an overall increase in individual welfare from anonymous and nonanonymous perspectives,which was higher among younger individuals.The welfare of the poor did not increase more than that of the nonpoor.These results shed light on the evolution of income distribution in China during the past decade's rapid economic growth.