Semiconductor Plasma

Experimental photograph of laser-pumped dense plasma condensation (EHL) in 2D semiconductors measured with time-resolved photoluminescence, absorption, and second harmonic generation microscopy. – Photograph credit: A. Bataller.

The physics of dense plasma finds validity in both real and quasiparticle charged systems.  My current research at NCSU explores a parameter space that is largely inaccessible in atomic plasmas, but is readily found in solid-state structures.  The temperature-density scaling relationships that determine many-body interactions, and ultimately condensation, can be realized for the electronic excitation quasiparticle (exciton) in semiconductors. This relatively low-energy platform grants access to a parameter space occupied by liquid condensation and  is heavily influenced by quantum effects. In the nearly 50 years since its discovery, electron-hole liquid (EHL) created within bulk semiconductors has been limited to cryogenic temperatures, and is often generated with high-intensity pulsed lasers. Due to their quantum confinement, reduced material screening, and long charge lifetime, the class of 2D semiconductors known as transition metal dichalcogenides are ideal materials for high-temperature EHL formation. At NCSU, we have recently discovered EHL condensation in monolayer molybdenum disulfide, which can be created above room temperature using less excitation power than a laser pointer!