Effects of growth temperature and thermal annealing on optical quality of GaNAs nanowires emitting in the near-infrared spectral range

Abstract

We report on optimization of growth conditions of GaAs/GaNAs/GaAs core/shell/shell nanowire (NW) structures emitting at ∼1 μm, aiming to increase their light emitting efficiency. A slight change in growth temperature is found to critically affect optical quality of the active GaNAs shell and is shown to result from suppressed formation of non-radiative recombination (NRR) centers under the optimum growth temperature. By employing the optically detected magnetic resonance spectroscopy, we identify gallium vacancies and gallium interstitials as being among the dominant NRR defects. The radiative efficiency of the NWs can be further improved by post-growth annealing at 680 °C, which removes the gallium interstitials.

UV Emission from GaN Wires with m-Plane Core–Shell GaN/AlGaN Multiple Quantum Wells

“…In this case, the higher activation energy was tentatively attributed to carrier localization induced by structural defects or QW thickness fluctuations . In the case of nanowires, a recent study of GaAs/GaNAs/GaAs core–shell heterostructures showed a biexponential decay of the PL intensity with temperature, with E 1 = 12 meV and E 2 = 63 meV, probably associated with the presence of gallium interstitials and vacancies . In our study, the nonradiative path activated at low temperatures seems to be an intrinsic phenomenon, which shows no correlation with QW thickness (Figure b,c).…”

“…47 In the case of nanowires, a recent study of GaAs/GaNAs/GaAs core-shell heterostructures showed a bi-exponential decay of the PL intensity with temperature, with E1 = 12 meV and E2 = 63 meV, probably associated with the presence of gallium interstitials and vacancies. 48 In our study, the non-radiative path activated at low temperature seems to be an intrinsic phenomenon, which shows no correlation with the QW thickness (Figures 6b,c). On the contrary, the non-radiative process dominant at high temperature (Pb) can be directly correlated with the drop of the I300 K/I10 K ratio observed in Figure 6a.…”

Effects of thermal annealing on localization and strain in core/multishell GaAs/GaNAs/GaAs nanowires

“…Post-growth annealing has several effects on the PL emission. First of all, it leads to an increase in the PL intensity, which was previously attributed to annealing-out of non-radiative defects 47 . Secondly, it causes a change in the low-energy slope of the PL peak.…”

“…Fabrication of complex NW heterostructures often involves post-growth annealing, which may represent a necessary step during device fabrication and is used to enhance transport and optical properties of the active material, due to annealing-out of grow-in defects [41][42][43][44] and improved alloy uniformity [45][46][47] . However, effects of such post-growth annealing on the global and local strain in NW heterostructures are yet to be understood.…”

INVESTIGATION OF ANNEALING TEMPERATURE ON STRUCTURAL, MORPHOLOGIES AND ELECTRICAL PROPERTIES Al/Y2O3/SiNWs/n-Si MOS CAPACITOR

“…One-dimensional (1D) semiconductor nanomaterials such as silicon nanowires (SiNWs) have received considerable attention in recent years, as these materials have unique electrical, chemical, magnetic, and optical properties, which are different from bulk material properties [1]- [4]. Research in this area is motivated by the possibility of designing semiconductor nanomaterials with applications leading to technological advances in radiation sensors, photovoltaic cell, thermoelectric, lithium-ion batteries, and areas of medical research [2], [3].…”