Investigation of Room Temperature Electron-Hole Liquid in Atomically Thin Semiconductors
Abstract
In semiconductors, optical excitation results in creation of electron and hole quasiparticles. The Coulomb and exchange interaction among these particles leads to rich variety of many-body effects that can change the optical and electronic response of the material significantly. The few particle interaction among these quasiparticles leads to exciton, biexicton and trion quasiparticles. At dilute concentrations these quasiparticles act like noninteracting gas. As the excitation density increase, similar to condensation of real ambient particles, quasiparticles in semiconductor can condense into a liquid state, i.e electron-hole liquid (EHL), at certain conditions. EHL is a quantum degenerate state and its formation leads to drastic changes in the electronic and optical properties of a material. For instance EHL is a metallic two-component fluid with a high energy density that could be transported across the material with speed of sound. Therefore creation of this exotic state provides additional tunability of the optical and electronic properties of semiconductors and could be the base of many different applications that utilize high energy density electronics. However the conditions that enable observation of EHL hinder the possibility of utilization of this exotic state in semiconductor based applications. Specifically EHL had been observed at cryogenic temperatures under extreme excitation conditions. Furthermore in many cases EHL is created using ultrafast excitations, which only form a transient EHL state that survives only for a short period of time. We most recently demonstrated that in single layer transition metal dichalcogenides, it is possible to excite EHL state at room temperature and under moderate excitation conditions. In this proposed work, we will investigate the excitation dynamics during this phase transition, and reveal processes that lead to degradation of material. The outcome of the research will enable continuous excitation of EHL state in 2D atomically thin semiconductors and pave the way for detailed characterization of this exotic state.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 16, 2018
- Source ID
- W911NF1710483
Entities
People
- Kenan Gundogdu
Organizations
- Army Contracting Command
- North Carolina State University
- United States Army