Effects of traps and shallow acceptors on the steady-state photoluminescence of quantum-well wires

Abstract

The effects of traps and shallow acceptors on the continuous-wave steady-state photoluminescence of GaAs-͑Ga,Al͒As quantum-well wires are studied at room temperature. The analysis is based on a quantum-mechanical calculation of the transition rates of radiative recombinations of excited-conduction electrons with free and bound ͑at acceptors͒ holes, and on a phenomenological treatment of the nonradiative rates associated with transitions involving conduction electrons falling into traps, and trapped electrons recombining with free holes. The various steady-state radiative and nonradiative e-h recombination lifetimes as function of the cw laser intensity are then obtained, as well as the dependence of the conduction-electron quasi-Fermi level ͑or chemical potential͒, and carrier densities on the laser intensity. We have also studied the laser-intensity dependence of various recombination efficiencies and of the integrated photoluminescence intensity. Finally, trap and impurity effects are shown to be quite important in a quantitative understanding of the room temperature steady-state photoluminescence of quantum-well wires.

Exciton capture and losses in a stacked submicron array of sidewall quantum wires on patternedGaAs(311)Asubstrates

“…2,7 Such an approach, however, neglects nonradiative recombination in the Qwell and Qwire regions as well as other loss mechanisms. As found previously in several works, [10][11][12][13] nonradiative decay channels can actually be of importance for the recombination dynamics even at low temperatures. Therefore, the measured ratio R PL probably reflects an overestimated transfer efficiency for the whole temperature range.…”

Impurity Binding Energy in Polar Quantum Dot with Finite Potential Barriers

“…The geometry now plays an overriding role in establishing binding energies and other impurity-related electronic properties, thus diminishing the influence of substituents. Over the past decades, most of the body of the experimental and theoretical work on the properties of impurities in semiconductor structures has already been carried out and has been devoted to the study of the electronic state in these microstructures [1][2][3][4][5][6][7][8][9]. As the situation of a hydrogenic impurity embedded in quantum dot has no exact solution it has been studied by the variational method, the effective mass approximation, the first-principles method, the effective bound-orbital model, the tight-binding self-consistent linear screening calculation, the plane wave semi-empirical pseudo-potential method with non-local potential and the Feynman-Haken method [10][11][12][13][14][15][16][17][18][19][20].…”