Laser-induced periodical microstructure in a Si substrate covered with a thin layer of silicon dioxide has been studied using KrF excimer laser irradiation for controlling the periodicity. It was found that KrF excimer laser irradiation can produce periodical microstructures in SiO2/Si samples by a single pulse if the laser fluence is large enough when the SiO2 thickness is small. When the SiO2 layer is thick and more than one laser pulse is required, circular patterns can be observed due to the interface defects. The periodicity of the ripple structure linearly depends on the SiO2 thickness. The formation of microstructure does not change the thickness of the SiO2 layer and the crystallinity in the Si substrate. The ripple structure formation in the SiO2/Si structure is related to the thermally generated surface waves. The existence of a SiO2 layer on Si substrate can change the surface tension during the melting of the Si interface and hence control the periodicity of the ripple formation. The lateral periodicity and vertical roughness of the ripple structures are within the range required for laser microtexturing of magnetic recording media.

Nanosecond surface structural changes during Q-switched laser annealing of a Si{111} crystal are studied with two-dimensional, time-resolved reflection of high-energy electron diffraction (RHEED) patterns obtained in real time synchronously with time-resolved optical reflectivity measurements. The detected Debye-Waller effect indicates the existence of a thermal process that results in melting of the surface. A transient crystalline surface phase is observed prior to recrystallization of the initial superstructure.

The local structure of Er-doped Si produced by a laser ablation technique is investigated by Er Lm-edge X-ray absorption fine structure (XAFS). The combination of an extended X-ray absorption fine structure (EXAFS) analysis and a X-ray absorption near edge structure (XANES) simulation indicate the atomic coordination of the optically active center; Er bonded with 6 oxygen atoms distorted form O h symmetry such as a C4v in this Si:Er system.

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High current densities of 1940 A/cm2 have been produced by a Cu/Be alloy photocathode, activated by 355 nm Q-switched laser pulses. The transient photocurrent, 7 ns full width, is utilized for the development of a pulsed reflection high energy electron diffraction (RHEED) system. Digital imaging and storage of single shot, two-dimensional diffraction patterns are achieved in real time with good spatial and intensity resolution.