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.
Bibliographical noteFunding Information:
This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) baseline funding, BAS/1/1664-01-01 and BAS/1/1647-01-05. B.J., T.K.N., and B.S.O. acknowledge the financial support from King Abdulaziz City for Science and Technology (KACST), Grant No. KACST TIC R2-FP-008, and KAUST baseline funding, BAS/1/1614-01-01.
© 2017 Author(s).
ASJC Scopus subject areas
- Physics and Astronomy(all)