Thermodynamic photoinduced disorder in AlGaN nanowires

Abstract

In this study, we examine thermodynamic photoinduced disorder in AlGaN nanowires through their steady-state and transient photoluminescence properties. We correlate the energy exchange during the photoexcitation and photoemission processes of the light–solid reaction and the generation of photoinduced entropy of the nanowires using temperature-dependent (6 K to 290 K) photoluminescence. We observed an oscillatory trend in the generated entropy of the system below 200 K, with an oscillation frequency that was significantly lower than what we have previously observed in InGaN/GaN nanowires. In contrast to the sharp increase in generated entropy at temperatures close to room temperature in InGaN/GaN nanowires, an insignificant increase was observed in AlGaN nanowires, indicating lower degrees of disorder-induced uncertainty in the wider bandgap semiconductor. We conjecture that the enhanced atomic ordering in AlGaN caused lower degrees of disorder-induced uncertainty related to the energy of states involved in thermionic transitions; in keeping with this conjecture, we observed lower oscillation frequency below 200 K and a stable behavior in the generated entropy at temperatures close to room temperature.

Heteroepitaxial β‐Ga2O3 on Conductive Ceramic Templates: Toward Ultrahigh Gain Deep‐Ultraviolet Photodetection

“…However, achieving optimal device performance requires extended optimization of material quality, device design, and process technology to compete against the technologically mature silicon carbide (SiC)‐ and gallium nitride (GaN)‐based commercial devices. [ 57–59 ]…”

Time–Energy Quantum Uncertainty: Quantifying the Effectiveness of Surface Defect Passivation Protocols for Low-Dimensional Semiconductors

“…We fitted the steady-state photoluminescence spectra with Cauchy–Lorentz distributions to extract the emission line widths as discussed in the Supporting Information. The transient photoluminescence decay curves were fitted and analyzed by using a biexponential decay model, which provided the most proper fit because of the multicenter recombination characteristics exhibited by the nanowires. ,,, Figures e and f show the In 0.32 Ga 0.68 N- and Al 0.14 Ga 0.86 N/Al 0.30 Ga 0.70 N-related steady-state and transient photoluminescence spectra, respectively, of the samples before and after the 1,2-ethanedithiol and potassium hydroxide passivation. We observe the reduction in energy dispersion after surface passivation, from Δ E = 0.311 to 0.267 eV for In 0.32 Ga 0.68 N and Δ E = 0.354 to 0.239 eV for Al 0.14 Ga 0.86 N/Al 0.30 Ga 0.70 N, implying reduced carrier recombination at defect centers.…”

“…In this article, we execute a quantitative study of the surface passivation effects on 1,2-ethanedithiol-treated In 0.32 Ga 0.68 N/GaN and potassium hydroxide-treated Al 0.14 Ga 0.86 N/Al 0.30 Ga 0.70 N nanowires using steady-state and transient photoluminescence. We previously studied the photoinduced entropy generation in similar nanowires using temperature-dependent steady-state photoluminescence, a phenomenon induced by strong exciton localization effects and charge carrier trapping by surface defect states. , Our previous thermodynamic approach was utilized to provide qualitative comparison between two materials (namely, In 0.32 Ga 0.68 N and Al 0.18 Ga 0.82 N) in terms of their luminescent refrigeration efficiencies. The quantity we termed “generated entropy” evolved with temperature, but because there is no scale, this evolution could be anywhere between vast and marginal.…”

Recent Advances on III‐Nitride Nanowire Light Emitters on Foreign Substrates – Toward Flexible Photonics

“…Some of the examples include: InN nanowires grown on bare glass substrates, GaN nanowires grown on amorphous Al x O y , GaN nanocolumns grown on silica and quartz, AlN nanowires synthesized on carbon nanotubes, and GaN nanowires grown on sapphire . Moreover, further beyond these growth efforts, III‐nitride nanowire LEDs and lasers on Si, metal, diamond, and 2D materials have also been demonstrated . In what follows, we describe these progresses.…”