Reduction in the concentration of cation vacancies by proper Si-doping in the well layers of high AlN mole fraction AlxGa1–xN multiple quantum wells grown by metalorganic vapor phase epitaxy

Abstract

Appropriate-amount Si-doping in the well layers significantly improved the luminescence efficiency of Al0.68Ga0.32N/Al0.77Ga0.23N multiple quantum wells. To understand the mechanisms, spatio-time-resolved cathodoluminescence measurements and self-consistent Schrödinger-Poisson calculations were carried out. The increase in the luminescence lifetime at room temperature, which reflects the decrease in the concentration of nonradiative recombination centers (NRCs), was correlated with increased terrace width of Si-doped wells. The results suggest the importance of H3SiNH2 doping-reactant formation that gives rise to enhanced decomposition of NH3 and provides wetting conditions by surface Si-N bonds, which reduce the total energy and concentration of NRCs composed of cation vacancies.

AlxGa1−xN‐Based Quantum Wells Fabricated on Macrosteps Effectively Suppressing Nonradiative Recombination

“…Figure plots the reported RT PL lifetimes as a function of the emission wavelength. It should be noted that as pointed out in multiple papers, the dominant recombination process at RT is nonradiative recombination, which is also true for our samples within our experimental condition. Therefore, Figure shows a trend of nonradiative recombination lifetimes.…”

“…In contrast, the RT PL lifetime of Al x Ga 1− x N QWs is 1.8 ns at a wavelength of 275 nm and becomes shorter as the emission wavelength decreases. A typical PL lifetime for Al x Ga 1− x N QWs emitting at a sub‐250 nm wavelength is a few hundred ps, as described in detail below . That is, increasing the Al composition shortens the lifetime, which is most likely due to the higher point‐defect densities in Al‐rich Al x Ga 1− x N.…”

263 nm wavelength UV-C LED on face-to-face annealed sputter-deposited AlN with low screw- and mixed-type dislocation densities

“…Both of well and barrier layers of the MQWs were shallowly Sidoped ([Si] ∼ 3-5 × 10 17 cm −3 ) to reduce the non-radiative recombination centers. 28,29) Figure 4 shows the crystalline quality of the UV-C LED epitaxial sample characterized via X-ray diffraction (XRD). The reciprocal space mapping (RSM) image obtained via ( 10 LED devices were fabricated using standard photolithography, inductively coupled plasma reactive ion etching, and electronbeam evaporation metallization.…”

Effect of Substrate Surface on Deposition of AlGaN: A Molecular Dynamics Simulation

“…Especially in deep ultraviolet LED (DUV-LEDs), AlGaN/AlN superlattices (SLs) are used for filtering dislocations and relieving stresses [7]. Moreover, it is applied in n and p electrodes as the container of negative and positive carriers, respectively [8,9]. In addition, it is a component of multiple quantum wells (MQWs), which serve as the active region for the recombination of carriers [10].…”