Ultrafast carrier dynamics in SnO_x thin films

摘要

We studied the carrier dynamics in a series of SnO_x thin films using femtosecond transient absorption (TA) spectroscopy. The observed carrier relaxation was found to be strongly dependent on thin film stoichiometry. The TA spectra corresponding to free carriers, trapped carriers, and state filling were observed in the picosecond time region for SnO_2, SnO_x, and SnO film, respectively. The TA decay kinetics of all films were best fit with a tri-exponential decay model with fast (1 ps), medium (～10 ps), and slow (ns) components. Our results revealed the carrier relaxation and recombination processes in SnO_x thin films, identifying the critical role of stoichiometry in photo-induced phenomena.