Title :
Direct measurement method for lattice spacing on regular crystalline surface using scanning tunneling microscope and laser interferometry
Author :
Aketagawa, Masato ; Rerkkumsup, Pongpun ; Takada, Koji ; Watanabe, Tomonori ; Sadakata, Shin
Author_Institution :
Dept. of Mech. Eng., Nagaoka Univ. of Technol., Niigata, Japan
Abstract :
This article describes the instrument used for direct measurement of the lattice spacing on regular crystalline surfaces using a scanning tunneling microscope (STM) as a detector and a phase modulation homodyne interferometer as the reference scale. It consists of a STM head with a YZ-axes tip scanner, a precise X-axis sample stage with flexure springs and interferometer optics. The three-dimensional atomic STM image of the crystalline surface can be obtained by combining the movements of the YZ-axes tip scanner and the X-axis sample stage. The displacement of the X-axis sample stage can be measured directly with the phase modulation homodyne interferometer, which can determine the optical path difference of a wavelength times integer with picometer resolution. To reduce the thermal deformation effects, the STM head and the sample stage were fabricated with low linear thermal expansion cast iron, the X-axis was selected as fast scanning and the measurement axis, and a thermostabilized cell with 0.05 K temperature fluctuation was employed. The lattice spacing on the crystalline surface can be determined from the number of lattice spacings along the X-axis in the atomic STM image and the measured displacement of the sample stage by the interferometer.
Keywords :
crystal structure; homodyne detection; light interferometry; optical modulation; phase modulation; scanning tunnelling microscopy; 3D atomic STM image; STM head; YZ-axes tip scanner; direct measurement method; flexure springs; highly-oriented pyrolytic graphite surface; interferometer optics; laser interferometry; lattice spacing; low linear thermal expansion cast iron; optical path difference determination; phase modulation homodyne interferometer; picometer resolution; precise X-axis sample stage; regular crystalline surface; scanning tunneling microscope; thermal deformation; thermostabilized cell; Atomic measurements; Crystallization; Lattices; Microscopy; Optical interferometry; Optical surface waves; Phase measurement; Phase modulation; Surface emitting lasers; Tunneling;
Conference_Titel :
Industrial Technology, 2002. IEEE ICIT '02. 2002 IEEE International Conference on
Print_ISBN :
0-7803-7657-9
DOI :
10.1109/ICIT.2002.1189337