Grant-in-Aid for General Scientific Research (C)
|Allocation Type||Single-year Grants|
Physical properties of metals
|Research Institution||Osaka University|
TAKEDA Seiji Osaka University, College of General Education, Assoc. Prof., 教養部, 助教授 (70163409)
HUA G. C. Osaka University, College of General Education, Research Associate, 教養部, 助手 (20224321)
MUTO Shunsuke Osaka University, College of General Education, Research Associate, 教養部, 助手 (20209985)
HIRATA Mitsuji Osaka University, College of General Education, Prof., 教養部, 教授 (00029638)
|Project Period (FY)
1989 – 1990
Completed(Fiscal Year 1990)
|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1990 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1989 : ¥1,700,000 (Direct Cost : ¥1,700,000)
|Keywords||Alloy Semiconductor / Ga-As-P compound / Transmission Electron Microscopy / Compositional Fluctuation / 濃度変動 / 透温電子顕微鏡法 / スピノ-ダル分解|
Structural property of thin layers of alloy-semiconductors has been investigated by means of transmission electron microscopy. The specimens observed in the present study were Ga-As-P, Zn-Se-S, Ga-Al-As and Ga-In-Al-As. The results of observation are summarized as follows.
1. One-dimensional compositional fluctuation in Ga-As-P
The material was grown by the VPE method on a GaP substrate. Fringe contrast was observed in dark field electron micrographs. This contrast results from the compositional fluctuation of As and P in a specimen. It was shown that the fluctuation was due to rotation of the substrate during crystal growth.
We defined the chemical sensitivity of a dark field image, i. e. The compositional derivative of image intensity. Analysis of a image intensity based on the chemical sensitivity indicated that a 200-type reflection was useful in detecting the compositional fluctuation and that a image with another reflection like 220 also has high sensitivity in some restricted exper
imental condition. This kind of analysis will be useful to detect compositional fluctuation caused by the spinodal decomposition in alloy semiconductors.
2. Interface structure in a strained layer super-lattice Zn-Se-S
The material was fabricated by the MOCVD method. Thin layers of the two compounds ZnS and ZnSe were stacked alternately. Misfit of lattice parameters of the two compounds was considerably large and the very wavy interface was observed.
3. Ga-As-Al alloys grown by the LPE method
The constitutional elements, Ga and Al were well homogenized and no compositional fluctuation was detected.
4. Ga-In-Al-As alloys grown by MBE method
It is well known that the alloy system exhibited the spinodal decomposition. However, the compositional fluctuation was not observed so far in the present specimens. It may be suggested that the growth method or growth temperature is related to the compositional fluctuation.
Heat treatment of thin foil specimens causes some evaporation of constitutional elements. In order to avoid this, we are planning to continue the Less