Investigating surface recombination velocity and bulk carrier lifetime in lithium tantalate using micro-photoconductance decay techniques

Abstract

Surface recombination velocity and bulk carrier lifetime in lithium tantalate were investigated using micro-photoconductance decay techniques. Polished and unpolished surfaces exhibited surface recombination velocities of 2.5 × 10⁴ cm/s and 3.5 × 10⁴ cm/s, respectively, with bulk carrier lifetimes ranging from 27 to 50 ns. X-ray photoelectron spectroscopy revealed that polishing reduces oxygen vacancies, decreasing surface recombination. Under 266 nm excitation, surface recombination dominated, whereas 355 nm excitation emphasized bulk recombination. Numerical modeling confirmed experimental trends. These findings enhance understanding of lithium tantalate for optoelectronic applications, enabling improved performance through control of surface and bulk recombination dynamics.