Quantum Dot-Like Behavior of Compositional Fluctuations in AlGaN Nanowires

Abstract

We report on the structural and optical properties of AlxGa(1-x)N nanowire sections grown by plasma-assisted molecular beam epitaxy on GaN nanowire bases used as a template. Based on a combination of scanning electron microscopy, microphotoluminescence, time-resolved microphotoluminescence, and photon correlation experiments, it is shown that compositional fluctuations in AlxGa(1-x)N sections associated with carrier localization optically behave as quantum dots. Moreover, most of the micro-optical properties of such fluctuations are demonstrated to be very little dependent on kinetic growth parameters such as AlxGa(1-x)N growth temperature and AlN molar fraction in the alloy, which govern the macrostructural properties of AlxGa(1-x)N sections.

Ultrafast, Polarized, Single-Photon Emission from m-Plane InGaN Quantum Dots on GaN Nanowires

“…26 Alternatively, for defect related emission, we would expect to observe a progression in peak intensity representing the transition from bound-to free-excitons as we increasingly thermalize the donor-bound excitons. 27 Indeed the wavelength change fits almost perfectly (R 2 = 0.996) to the O'Donnell-Chen model of temperature dependence of band gaps (see SI for details), and as such we can conclude that the emission features presented do correspond to semiconductor localization centers such as those observed in TEM. The variation of linewidth with increasing temperature gives us insight into the influence of phonons on these m-plane QDs.…”

Lateral‐Polarity Structure of AlGaN Quantum Wells: A Promising Approach to Enhancing the Ultraviolet Luminescence

“…The best‐performing UV LEDs have been grown on the III‐polar (0001) structure so far. [1a] Nevertheless, the usage of N‐polar (000) nitride films has also gained attentions recently due to their distinct advantages such as reduced efficiency droop in the application of LEDs, enhanced electrical field distribution in p‐i‐n diodes, and susceptibility to wet etching, which can be used for nanostructure fabrication …”

Quantified hole concentration in AlGaN nanowires for high-performance ultraviolet emitters

“…Moreover, the composition and doping fluctuations in/between AlGaN nanowires strongly influence the electrical properties of the nanowire array. 31,37,38 The hole concentration in nanowire arrays is typically estimated using a planar GaN : Mg epilayer as a reference. 30 However, a discrepancy exists between the estimated and actual values because of different morphologies and growth conditions.…”