Hyped-sounding and dynamic diffraction grating test stand

Unit: Faculty of Physics

Keywords: Hyped-sounding, dynamic diffraction grating test, carrier lifetime, diffusivity, semiconductors

Responsible person: Dr. Ramūnas Aleksėjūnas, tel. +37060034126,

Stand suitable for measurement of key electrical parameters like carrier diffusivity, mobility, lifetime, surface recombination velocity, using conventional pump-probe and know-how transient grating techniques.

These techniques are based on excitation of the material or a device by a short laser pulse of required wavelength and spatial shape and consequent observation of carrier dynamics by delayed pulses. Advantage of this approach lies in contactless and non-destructive nature of measurement techniques allowing determination of key electrical parameters of a semiconductor or device structure.
Diffusivity above 0.1 cm2/s and lifetime above 300 fs can be measured in materials with forbidden energy gap within 0.6-5.8 eV. If needed, the described parameters can be investigated within wide temperature (10-700 K) and injection (1018-1020 cm-3 carrier densities) ranges.
Measurement setup is based on „Ekspla" lasers PL2143 and PL2243, OPG PG401, „Light Conversion" laser Pharos and OPA Orpheus, „Cryo Industries" helium and nitrogen cryostats, completed with all necessary optical, mechanical and data acquisition equipment.

Application. Contactless determination of free carrier lifetime and diffusivity in semiconductors and devices.