Strongly enhanced shift current at exciton resonances in a noncentrosymmetric wide-gap semiconductor.

ABSTRACT: Excitons are fundamental quasiparticles that are ubiquitous in photoexcited semiconductors and insulators. Despite causing a sharp and strong photoabsorption near the interband absorption edge, charge-neutral excitons do not yield photocurrent in conventional photovoltaic processes unless dissociated into free charge carriers. Here, we experimentally demonstrate that excitons can directly contribute to photocurrent generation through a nonlinear light-matter interaction in a noncentrosymmetric semiconductor CuI. Epitaxial thin films of CuI exhibit a substantial enhancement of photocurrent at exciton resonance energies even below the bandgap. From the light polarization dependence, this photocurrent is identified to be shift current, a nonlinear photocurrent driven by the change in the geom

SUBMITTER: Nakamura M 

PROVIDER: S-EPMC11569220 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature