Estudo da dinâmica de portadores em diodos de tunelamento ressonante tipo-p
Ver/
Fecha
2007-02-27Autor
Galeti, Helder Vinicius Avanço
Metadatos
Mostrar el registro completo del ítemResumen
Photoluminescence spectroscopy has been used to provide important insight
on the tunneling dynamics of carriers in double barrier diodes. In this work, we have
performed time-resolved photoluminescence measurements in symmetric and
asymmetric p-type GaAs/AlAs resonant tunneling diodes in order to study the
tunneling dynamics of photocreated minority electrons. We observed several peaks
in the current voltage characteristics (I-V) associated to the resonant tunneling of
holes through different quantum well heavy- and light-hole sub-bands. Under light
excitation, we have observed the developing of additional peaks in the I-V curve. For
the asymmetric structure, two peaks were observed and associated to the exciton
assisted tunneling and resonant tunneling of photogenerated electrons. We have
studied the temporal evolution of the GaAs contact and quantum well (QW) emission
versus the applied bias voltage. For the QW, the luminescence comes solely from the
recombination between the lowest-energy confined levels in the QW even when the
device is biased at higher tunneling resonance peaks. For both structure, the PL
decay depends on the applied voltage and presents a bi-exponential decay for some
values of bias. The results revealed a markedly long PL decay at the bias voltage
associated the exciton assisted tunneling resonance in the current voltage
characteristic. For the GaAs emission, we observed a weak dependence of the PL
intensity versus voltage and a mono-exponential decay. We analyze our results
considering the diffusion and tunneling of minority electrons in the structure