Auger Recombination in Two-dimensional Quantum Confined Semiconductors

Title Auger Recombination in Two-dimensional Confined Semiconductors Application No. 2017637 Principal Investigators: Prof. Efrat Lifshitz, Schulich Faculty of Chemistry, Technion, Israel Prof. Xiaoyang .Y Zhu, Department of Chemistry, Columbia University, USA

The present U.S.-Israeli collaborative project will focus on a fundamental phenomenon, named Auger recombination, in two-dimensional (2D) semiconductors such as transition metal dichalcogenides and halide-perovskites. The 2D structures can be fabricated with nearly atomistic thickness, endowing the materials with unique electric, optical and magnetic properties, with a distinctive interest for various opto-electronic and spintronics applications. An Auger process is a many-body effect, in which a non-radiative recombination of an electron-hole pair occurs efficiently by transferring energy to a third charge carrier. Unfortunately this process is detrimental for device applications. Although it was investigated extensively in zero-dimensional quantum dots, there is little knowledge about this affect in 2D materials. To fill this critical knowledge gap and formulate rational strategies for the control of Auger recombination rates, the principal investigators (PIs) will take advantage of their complementary expertise and carry out a joint research program to quantitatively probe Auger recombination in the mentioned nanostructures.

The PIs propose to experimentally probe Auger recombination in these model systems using the following methodologies: (1) femtosecond time-resolved two-photon photoemission spectroscopy, to directly detect Auger electrons as they scatter into particular energy and momentum spaces; (3) magneto-optical spectroscopy combined with microwave and magnetic-resonance perturbations, to identify and quantify the identify and quantify the products of an Auger process and their relation to structural issues, such as thickness fluctuations or crystallographic defects. The study would shed light on a debating topic and moreover, should supply suggestions of how to mitigate The Auger phenomenon.