| Autor: |
Chichibu, Shigefusa F., Shima, Kohei, Uedono, Akira, Ishibashi, Shoji, Iguchi, Hiroko, Narita, Tetsuo, Kataoka, Keita, Tanaka, Ryo, Takashima, Shinya, Ueno, Katsunori, Edo, Masaharu, Watanabe, Hirotaka, Tanaka, Atsushi, Honda, Yoshio, Suda, Jun, Amano, Hiroshi, Kachi, Tetsu, Nabatame, Toshihide, Irokawa, Yoshihiro, Koide, Yasuo |
| Předmět: |
|
| Zdroj: |
Journal of Applied Physics; 5/14/2024, Vol. 135 Issue 18, p1-20, 20p |
| Abstrakt: |
For rooting the development of GaN-based optoelectronic devices, understanding the roles of midgap recombination centers (MGRCs), namely, nonradiative recombination centers and deep-state radiative recombination centers, on the carrier recombination dynamics is an essential task. By using the combination of time-resolved photoluminescence and positron annihilation spectroscopy (PAS) measurements, the origins of major MGRCs in the state-of-the-art GaN epilayers, bulk crystals, and Mg-implanted layers were identified, and their concentrations were quantified for deriving the capture coefficients of minority carriers. In this article, potential standardization of the room-temperature photoluminescence lifetime for the near-band-edge emission (τ PL RT ) as the concentration of major MGRCs well below the detection limit of PAS is proposed. For n-GaN substrates and epilayers grown from the vapor phase, τ PL RT was limited by the concentration of carbon on N sites or divacancies comprising a Ga vacancy (VGa) and a N vacancy (VN), [VGaVN], when carbon concentration was higher or lower, respectively, than approximately 1016 cm−3. Here, carbon and VGaVN act as major deep-state radiative and nonradiative recombination centers, respectively, while major MGRCs in bulk GaN crystals were identified as VGa(VN)3 vacancy clusters in Na-flux GaN and VGa or VGaVN buried by a hydrogen and/or VGa decorated with oxygen on N sites, VGa(ON)3–4, in ammonothermal GaN. The values of τ PL RT in n-GaN samples are compared with those of p-GaN, in which τ PL RT was limited by the concentration of VGa(VN)2 in Mg-doped epilayers and by the concentrations of VGaVN and (VGaVN)3 in Mg-implanted GaN right after the implantation and after appropriate activation annealing, respectively. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
