Phonon Scattering Study of Strain-Effects in Heterostructure.

目前联合研究的重点是要解决以下几个关键问题或困难：(1)精确控制热脉冲高频声子的产生和(2)高灵敏度和快速的声子探测，(3)良好控制的SiGe系统薄膜的制备，(4)正确的数据积累和精确分析，以及它们在电子器件上的应用。(1)采用新的方法和设计，利用光刻技术来产生高频声子，以获得高时间和空间分辨率。提出了一种将0.5mmphi的同轴电缆连接到加热器和测辐射热计上的新技术，避免了电磁制动对测辐射热计的影响。(2)10 nm厚的铝薄膜测辐射热计是在5×10℃的氧气气氛中蒸发的，在1.35K具有陡峭的宽/线性跃迁斜率，其灵敏度远远高于以往的报道。结晶学S…更多的结构被揭示为六方结构，这是本项目的首次发现和显著成果之一。采用涡轮分子泵和正胶光刻新技术，在无油真空条件下获得了良好的重复性和优异的质量。(3)采用射频溅射法制备了SiGe系薄膜，在应变边界处观察到了较强的模式转换。(4)从理论上讲，Miyasato和Wigmore与Lacaster大学的A G Kozorezov发展了计算，其中我们模拟了热脉冲从粗糙表面的散射，作为上述的反射实验。如上所述，本项目的技术和理论研究在高频声子与非常薄的薄膜和/或电子的相互作用领域取得了重大突破，即低维电子气。较少

The most important points in the present joint research is that some essential problems or difficulties should be overcome, which are : (1) precisely controlled heat pulse high frequency phonon generation and (2) high sensitive and quick phonon detection, (3) preparation of good controlled siGe system films, (4) correct data accumulation and their precise analyzes, and their (5) application to electronic devices.(1) The heater wihch generates high frequency phonons was prpared by photolithography technology with new method and design to get high resolution in time and space. A new technique to connect coaxial cable of 0.5 mmphi to the heater and the bolometer was developed and to avoid the electro-magnetic brake-through into the dtector.(2) The aluminium thin film bolometer of 10nm thick was evaporated in 5*10^<-6> Torr of oxgen atmosphere, wihch has steep and wide/linear transition slope at 1.35 K,and its sensitivity is far higher than that reported in the past. The crystallographic s … More tructure was revealed to be hexagonal, which is the first obervation and one of remarkable results of the present project. A good reproducibility and its outstanding quality were obtained in oil-free vacuum by turbo-molecular pump andby new photolithography technique by positive-resist process.(3) SiGe system film was prepared by RF-sputtering method, and a strong mode conversion at strained boundary was observed. But showed that the electric conductivi-tiy was not enough for EEMT,then the materials for HEMT is to be offered by HITACHI and other laboratories.(4) From the theoretical point, Miyasato and Wigmore developed calculation with A G Kozorezov at Lacaster University, in which we have modelled the scattering of heat pulse from rough surface, as reflection experiment as mentioned above. The effect of long-range irregu-larities was calculated in the eikonal approximation.As shown above, the technological and theoretical researches of the present project have made a great break-through in the field of interaciton of high frequency phonons with very thin films and/or electrons in it, namely low dimensional electron gas. Less