Determination of the dynamic deformation tensor by time-resolved triple-crystal diffractometry.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Physics

Background:

• Understanding material response to pulsed lasers is crucial for applications in semiconductor manufacturing and laser-based processing.
• Gallium arsenide (GaAs) is a vital semiconductor material with unique optoelectronic properties.
• Characterizing dynamic deformations in crystalline materials requires advanced measurement techniques.

Purpose of the Study:

• To investigate the dynamic deformation tensor of a gallium arsenide wafer following ultrafast laser excitation.
• To analyze the relaxation process and identify transient structural changes induced by the laser pulse.
• To validate experimental findings with theoretical models of material behavior.

Main Methods:

• Utilized triple-crystal X-ray diffractometry coupled with time-resolved measurement techniques.
• Employed a digital storage oscilloscope and a fast X-ray detector for high temporal resolution.
• Applied a 130 fs laser pulse to induce ultrafast excitation in the GaAs wafer.

Main Results:

• Determined the time dependence of the deformation tensor in the gallium arsenide wafer.
• Observed instantaneous expansion and the formation of a localized convex surface post-laser pulse.
• Identified the emergence of a flexural standing wave during the material's relaxation phase.

Conclusions:

• The observed flexural standing wave during relaxation is well-explained by classical elasticity theory for thin plates.
• Time-resolved X-ray diffractometry is effective for probing ultrafast laser-induced dynamics in semiconductors.
• This study provides insights into the mechanical response of gallium arsenide to intense, short laser pulses.