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Showing 1 to 8 of 8 for “"free excitons"”.
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Transport of free excitons and electron-hole droplets in silicon and germanium
… of the transport properties of photo-excited free excitons (FE) and electron-hole droplets (EHD). The mobilities of both species are largely controlled by interaction with lattice phonons. Non-equilibrium phonon fluxes are capable of moving EHD macroscopic distances in ultrapure crystals of …
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Interaction of non-equilibrium phonons with electron-hole plasmas in germanium
… with lineshapes associated with a Fermi fluid, free excitons and. excitonic molecules. Evidence is found that the EHP undergoes an additional first order phase transition to free excitons above the established liquid-gas critical temperature."
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Bose-Einstein condensation of excitons in cuprous oxide
Free excitons provide the only experimental system other than helium in which the behavior of particles with mass is known to follow Bose-Einstein statistics. I present experimental observations of the kinetic energy distribution of excitons in the direct-gap semiconductor Cu$\sb2$O, both the …
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OPTICAL CHARACTERIZATION OF WIDE ENERGY AGP GROUP III-NITRIDE SEMICONDUCTORS
… grown on (1000)-plane sapphire substrates. Free exciton transitions, bound exciton transitions and longitudinal optical (LO) phonon-assisted exciton transitions were observed in undoped GaN samples. By applying Permogorov's theory, we gave a reasonable explanation to the temperature …
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Luminescence studies of photoexcited electron-hole plasmas in silicon and germanium
… in stressed Ge. When EHL condenses from a gas of free excitons (FE), t:NJ phase changes occur: the gas-liquid transition and an insulator-metal transition. By using a strain-confinement technique, we were able to observe the phase changes both spectrally and spatially. We fomxl evidence that the …
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I. Excitonic phase diagram in Si: evidence for two condensed phases ; II. Motion of photoexcited carriers in GaAs/Alx̳Ga1̳-̳x̳As multiple quantum wells : anomalous confinement at high densities
… At low temperatures and sufficient densities, free excitons in Si and Ge undergo a simultaneous gas-liquid and insulator-metal transition into droplets of electron-hole liquid. Some previous theoretical and experimental studies have suggested that, under certain values of density and …
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Excitons in Two-Dimensional Materials: from Many-Body Physics to Quantum Technologies
… recombination of bound electron-hole pairs, or excitons. Their unique band structure gives rise to rich excitonic spectra where the excitons possess large binding energies in the order of meVs due to the 2d nature of the material. In this Thesis I fi rst explore complex exciton species within a …
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Exciton Dynamics and Anisotropy in 2D Metal Organochalcogenolate Semiconductors
… interactions among quasiparticles (such as excitons, phonons, and photons) due to its large exciton binding energy, strong exciton-lattice interactions, and natural photonic cavity structure. From a technological standpoint, its narrow blue emission, a tunable bandgap through composition …