Polarization resolved luminescence in asymmetric n-type GaAs∕AlGaAs resonant tunneling diodes

Abstract

We have investigated the polarized emission from a n-type GaAs/ AlGaAs resonant tunneling diode under magnetic field. The GaAs contact layer emission shows a large constant negative circular polarization. A similar result is observed for the quantum well, but only when electrons are injected from the substrate, while for inverted biases, the polarization tends to become positive for small voltages and large laser excitation intensities. We believe that the quantum well polarization may be associated to the partial thermalization of minority carriers on the well subbands and is thus critically dependent on the bias-controlled density of carriers accumulated in the well.

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

“…2(b) shows the voltage dependence of the QRs PL intensity and the I(V) characteristics curve. Usually, the PL intensity and I(V) characteristics curve of RTDs are correlated as will be discussed below [10][11] . It was observed that the PL intensity increases with the increase of applied voltage up to about 0.4 V which corresponds to the voltage range that gives important photocurrent values.…”

“…In a simple model, the PL can be given by the product of the electron and hole density. It is well known that the carrier density in the QW increases with voltages associated to resonant tunneling condition [10][11] . Therefore, peaks of PL intensity are expected to be observed around the hole or electron resonance and therefore are correlated to the I(V) characteristics curve.…”

“…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] . 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 .…”

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

“…Since hole spin relaxation times are much shorter than electron spin relaxation times, the improvement of spin injection efficiency in those structures is a difficult issue. In the last years, it was also shown that spin-polarization of holes in p-i-p Resonant Tunneling Diodes (RTDs) can be voltage-selected, which makes such device attractive for spintronic applications [9][10][11][12]. A possible improvement of spin-LEDs could thus be obtained by using the resonant tunneling effect in association of a layer of GaMnAs acting as a spin injector in p-i-n RTDs.…”