Temporal Evolution of Photothermal-Induced Rayleigh Wave and Plate Deformation as an Interference in the Transient Kinetics of Photoinduced Carrier Recombination of a Rutile Titanium Dioxide Single Crystal

Abstract

The dynamic properties of photothermal processes occurring after the initial photogenerated carrier recombination in the flash photolysis of a semiconductor plate sample probed with a reflected infrared beam are reported in this work. Transient kinetics pertaining to the photothermal processes always appear as interfering signals in that of the photogenerated carrier recombination and should be distinguished and excluded. We observed that the photothermal-induced Rayleigh wave occurs immediately after the photogenerated carrier recombination that is then followed by the photothermal-induced flexural vibration of the sample substrate with a set of intrinsic frequencies as reported in our previous work (Appl. Spectrosc. 2013. 67(5): 506–512). When these two faster types of waves decay, the transient decaying signal from the plate deformation due to the inhomogeneous temperature field remains for much longer than 22 ms. Thus, all three types of the photothermal dynamic processes of different temporal properties induced by the pulsed laser on an absorbing semiconductor thin plate are clearly identified.