What Is Grazing Incidence Small Angle X-ray Scattering (GISAXS)?

GISAXS is an advanced technique for analyzing the state and size distribution of nanoparticles in thin films on substrates, as well as nanoscale surface and interface structures. GISAXS is widely utilized for evaluating various thin film materials, including semiconductor quantum wires, magnetic films, and polymer films, as well as for observing the early stages of thin film crystal growth.

Grazing-incidence method

The region near the sample surface is of primary interest in thin film analysis. GISAXS is a variation of Small Angle X-ray Scattering (SAXS), a technique that measures X-rays scattered at small angles (up to a few degrees). To effectively apply SAXS to thin film samples, GISAXS analysis is performed as follows: 

X-rays are directed onto the surface of a sample at a very small angle (typically less than 1º), effectively targeting this area. Since the X-rays only penetrate a limited depth, GISAXS allows for the detection of small-angle scattering signals from the thin film and the film-substrate interface.

SAXS signals from the samples are efficiently captured using a 2D detector with a large detection area and high dynamic range. By analyzing the relationship between scattering angle and intensity, key structural parameters—such as average particle size, size distribution, and long-period structures—can be determined. Additionally, the image data recorded by the 2D detector can be used to extract a SAXS profile along a specific direction of interest. This allows for separate evaluations of the thin film’s growth or stacking direction, its in-plane structure, and the film-substrate interface.

With these capabilities, GISAXS is expected to play a crucial role in the development of advanced materials, where miniaturization and three-dimensional structural control are essential.