Control and LT-undoped rocking curves for the as-grown and annealed (350–600 °C) samples. The rocking curves are referenced to the substrate peak. The inset shows the zoomed in area of the 0th order QW satellite peak for the LT-Undoped sample. The shift in the peak position is clearly seen and the arrow indicates the trend with annealing temperature.
PL spectra as a function of annealing temperature for the control sample (VMBE1993). A strong PL signal is shown at 1.55 μm which decreases as the annealing temperature is increased. The inset shows the PL response of the LT undoped sample (VMBE2001).
Noise spectra as a function of annealing for the samples doped throughout the structure (VMBE) and the samples with modulated doping (XMBE).
Absorption spectra of InGAs/InAlAs MQWs at room temperature for the (a) normal temperature growth VMBE as-grown sample and (b) LT VMBE undoped and LT VMBE heavily doped as-grown samples.
(a) Room temperature absorption spectrum for the heavily doped XMBE as-grown samples. (b) Relevant absorption coefficient. The absorption coefficient was calculated using the total well thickness (7000 Å).
Hall effect results for the VMBE samples showing the effect of the Be incorporation and the post growth annealing in the carrier concentration and mobility.
Hall effect results for the XMBE samples showing the effect of the Be incorporation and the post growth annealing in the carrier concentration and mobility.
Sheet resistance as a function of annealing for the LT undoped and heavily doped samples compared with the values of the LT GaAs and the highest reported in the literature.
Carrier dynamics for the three samples that provided the desired optical and electrical characteristics for prospective THz emitters and detectors.
Carrier lifetime as a function of annealing temperature for the low doped and heavily doped VMBE samples. Note the different time scales used in the figure.
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