Ultrafast dynamics of MnSi1.7 film studied by pump–probe technique

Abstract

Manganese silicide (MnSi[Formula: see text]) semiconductor thin films with a thickness of 80 nm are prepared by magnetron sputtering deposition technology. The reflectivity change of thin film samples is studied by femtosecond (fs) pump–probe technique under different pump pulse energies and the laser pulse width is 120 fs. The results show that the transient reflectivity increases within a time-scale of about 100 fs. Then, a fast decay of reflectivity occurs in 0.6 picosecond (ps), and it is mainly due to the carrier–carrier scattering. Next, a slower decay of the reflectivity on a time-scale of dozens of ps is detected, and the Auger recombination and diffusion are the main processes. The effective mass of electron and hole in MnSi[Formula: see text] film are calculated by using the pseudo-potential plane wave method on first-principles methods. The effective mass of electron is 0.25[Formula: see text] ([Formula: see text] is the electron mass), while 0.13[Formula: see text] for hole. Experimental results are explained with the results of theoretical simulation.

Pulse energy and wavelength-dependent ultrafast dynamics of SnSe2 thin film studied by transient absorption

“…Thus, the fast decay component (1 ∼ 2 ps) could be assigned to the carrierphonon scattering and carrier-carrier scattering in the SnSe 2 thin film. Similar timescale and carrier decay process has been observed in other semiconductor materials [37,38]. The relatively medium decay is the relaxation of the carrier toward the deeper trap states.…”