Screening effect on the binding energy of the exciton in quantum wires

Abstract

This paper describes using the finite difference method to study the screening effect on the binding energy of excitons in quantum wires (QWRs). We have derived an analytical formula for the effective screened interaction potential between an electron and a hole in an exciton. The exciton binding energy as functions of the screening length, carrier density, and QWR width is calculated and is found to be sensitive to the screen length when the length is less than 1 × 103 Å. Furthermore, when the screen length is less than 3 × 102 Å, the exciton binding energy decreases rapidly with decreasing screen length. It is also found that the wider the QWR is, the more pronounced the screening effect will be. The transition from a dilute exciton gas to a dense electron-hole plasma in a QWR is clearly shown on a phase diagram for the carrier density-temperature plane.

Carrier-density-dependent recombination dynamics of excitons and electron-hole plasma in m -plane InGaN/GaN quantum wells

“…Note that, due to Coulomb screening and phase-space filling effects, E b continuously decreases as n increases [20]. To describe such a behavior in a simple way, we use an equation analogous to the Debye screening model [30]:…”

Ultralong spin lifetimes in one-dimensional semiconductor nanowires

“…In the 3D NWs we find n 3D = 8 ×10 16 cm −3 , whereas n 1D ≈ 1 ×10 6 cm −1 in the 1D NWs. Such carrier densities characterize an e-h system slightly above the metal-insulator (or Mott-) transition-the notion of an exciton is therefore no longer strictly applicable in the pulsed excitation regime of our experiments [30][31][32] -and we thus use the term e-h pair. In Fig.…”

Yukawa model of screening in low-dimensional excitons: diagonalization, perturbation, variation, and resummation analysis

“…Nonetheless, excellent agreement with density-dependent exciton absorption in GaAs [6] and ultrafast screening dynamics of ZnO excitons has been found [10]. Moreover, the static Yukawa model has been applied to screening of excitons in one-and two-dimensional semiconductors [7,8,11] as well as bulk materials [5,6,9,10].…”

“…Important examples include plasma interactions, electrolytes, and electron-hole pairs, i.e. excitons, in semiconductors [2][3][4][5][6][7][8][9][10][11]. Hence, although the Yukawa model as introduced in a very different context, it has been widely applied in condensed matter physics.…”

“…It plays a significant role in semiconductor physics [4]. In particular, following the pioneering work by Gay [5], exciton screening due to free carriers from doping or intense excitation has frequently been treated using Yukawa potentials [5][6][7][8][9][10][11] or the closely related Hulthén model [6,12]. Fundamentally, exciton screening is a dynamical process but a static approximation is frequently adopted due to the inherent simplicity.…”