Modulation of photocarrier relaxation dynamics in two-dimensional semiconductors

Abstract

Semiconductor photocarriers: Exploring excitons in two dimensions Electrons and positively charged regions in semiconductors known as holes can form tightly bound states called excitons, offering new opportunities in optoelectronics and in ‘valleytronics,’ which exploits the effects of valleys and peaks in an energy landscape. The excitons display particle-like properties, so are described as quasiparticles. Fengqiu Wang and colleagues at Nanjing University, in China, review many technical aspects of the creation and control of excitons in single layer (2D) semiconductor sheets. The restrictions of 2D materials promote unique exciton behavior and strong light-matter interactions. The authors focus on the ability of excitons to act as photocarriers of absorbed light energy, and on the relaxation processes that can release the energy. Learning how to control exciton formation, interactions and relaxation will be crucial for using them to develop novel optoelectronic and photonic devices.