X-ray standing waves generated by dynamical Bragg diffraction were used as an element-specific structural probe for investigating Ga and Sb adsorption on Si(001). Using the (004) and (022) reflections, we precisely measured Ga and Sb ad-dimer bond lengths and ad-dimer heights above the bulk-extrapolated Si(001) surface. The room temperature  thermal vibration amplitudes of Ga and Sb adatoms on Si(00l) were also directly determined by combining the fundamental (004) and high-order harmonic (008) X-ray standing wave measurements. These high-resolution measurements reveal important quantitative structural information regarding the dimerized surface structures, and provide a stringent test for structural models proposed by various theoretical calculations. In this paper, we also give an over-view of the X-ray standing wave technique and its application in investigating surface structure and dynamics.
Qian, Y.; Lyman, P. F.; and Bedzyk, M. J.
"X-Ray Standing Wave Studies of Ad-Dimers on Si(001),"
Scanning Microscopy: Vol. 9
, Article 5.
Available at: https://digitalcommons.usu.edu/microscopy/vol9/iss4/5