Te incorporation in GaAs_1−xSb_xnanowires and p-i-n axial structure

Abstract

We report on in situ Te-doping in GaAs1−xSbx nanowires (NWs) grown via self-assisted molecular beam epitaxy. Enhanced Te incorporation in the NW at higher Te cell temperature was attested by the broadening of the x-ray diffraction peak and the presence of a strong coupled-LO phonon mode in the Raman spectra. Te-doping was estimated from the shift in the coupled-LO phonon mode to be ∼2.0 × 1018/cm3. The surfactant nature of the Te modulated the growth kinetics, which was manifested in an enhanced radial growth rate with improved photoluminescence (PL) characteristics at both room temperature (RT) and 4 K. No noticeable planar defects were observed as ascertained from the high-resolution transmission electron microscopy images and selected-area electron diffraction patterns. Finally, we demonstrate the experimental realization of a GaAs1−xSbx axial p-type/intrinsic/n-type (p-i-n) structure on a Si substrate with Te as the n-type dopant. The GaAs1−xSbx p-i-n NW structures exhibited rectifying current–voltage (I–V) behavior. The dopant concentration and the transport parameters estimated from the PL spectra and I–V curve were found to be in good agreement.