Thermal equilibrium governing the formation of negatively charged excitons in resonant tunneling diodes

Abstract

The thermal equilibrium of the formation of negatively charged excitons is studied in this work, by measuring the current and quantum-well photoluminescence in biased resonant tunneling double barrier diodes. We observe that the intensity ratio of negatively charged and neutral excitons depends linearly on the current for fixed temperature and illumination conditions. We propose that the results can be interpreted in terms of a mass-action law governing the concentrations of neutral and charged excitons and free electrons. Measurements at different temperatures and bias yield an electron concentration and a dwell time in the well that are in good agreement with the values previously reported in the literature. We also analyze the dependence of the luminescence on excitation intensity.

Spin Polarization of Carriers in InGaAs Self-Assembled Quantum Rings Inserted in GaAs-AlGaAs Resonant Tunneling Devices

“…Strong oscillations of circular polarization degree (CPD) were observed in RTDs under applied bias and high magnetic fields with maximum values around the resonant peak voltages 8 . In addition, it was evidenced the formation of highly spin-polarized two dimensional (2D) 3 gases under high magnetic fields which are responsible for spin polarized injection of carriers into the quantum well (QW) of the RTDs 11 .The formation of excitonic complexes in RTDs at hole and electron resonant tunneling condition was also demonstrated 12,18 . The physical properties of RTDs containing selfassembled InAs quantum dots (QDs) were also investigated [13][14][19][20][21][22] .…”

“…Resonant tunneling diodes (RTDs) have also been a research focus for many years [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . Several works investigated their fundamental physical properties and possible potential applications in spintronics [8][9][10][11][12][13][14][15][16][17] .…”

“…Several works investigated their fundamental physical properties and possible potential applications in spintronics [8][9][10][11][12][13][14][15][16][17] . For example, it was shown that spin polarization of carriers in RTDs can be voltage and light dependent under magnetic field [8][9][10] .…”

Hole spin injection from a GaMnAs layer into GaAs–AlAs–InGaAs resonant tunneling diodes

“…This increase could be due to small differences of the samples parameters as well as some residual Mn concentration and/or variations of the carrier densities in the QWs including the possible formation of charged excitons [13]. These factors may affect the g-factors of the structures.…”

“…We also remark that the GaAs QWs bands have significantly larger linewidths than the InGaAs QWs. This indicates that a significant charge build-up must occur in the GaAs QWs [13] of the biased RTDs. The excitonic spin-splitting of the QW emission bands from the S0 structure are almost zero (~1 meV for the GaAs and ~0 meV for the InGaAs QW) in agreement with previous results [9].…”