Nanosecond light induced, thermally tunable transient dual absorption bands in a-Ge5As30Se65 thin film

TL;DR

This study reports the first observation of nanosecond laser-induced transient dual absorption bands in a-Ge5As30Se65 thin films, which are thermally tunable and exhibit temperature-dependent kinetics, revealing potential for optical switching applications.

Contribution

It introduces the first observation of thermally tunable, nanosecond laser-induced dual absorption bands in a-Ge5As30Se65 thin films with temperature-dependent decay kinetics.

Findings

Dual absorption bands observed in a-Ge5As30Se65 thin films.

Absorption bands are thermally tunable with contrasting behavior.

Decay kinetics strongly depend on temperature.

Abstract

In this article, we report the first observation of nanosecond laser induced transient dual absorption bands, one in the bandgap (TA1) and another in the sub-bandgap (TA2) regions of a-Ge5As30Se65 thin films. Strikingly, these bands are thermally tunable and exhibit a unique contrasting characteristic: the magnitude of TA1 decreases while that of TA2 increases with increasing temperature. Further, the decay kinetics of these bands is strongly influenced by the temperature, which signifies a strong temperature-dependent exciton recombination mechanism. The induced absorption shows quadratic and the decay time constant shows linear dependence on the laser beam fluence.