The origins and properties of intrinsic nonradiative recombination centers in wide bandgap GaN and AlGaN

S. F. Chichibu, A. Uedono, Kazunobu Kojima, H. Ikeda, K. Fujito, S. Takashima, M. Edo, K. Ueno, S. Ishibashi

Research output: Contribution to journalArticlepeer-review

91 Citations (Scopus)


The nonradiative lifetime (τNR) of the near-band-edge emission in various quality GaN samples is compared with the results of positron annihilation measurement, in order to identify the origin and to determine the capture-cross-section of the major intrinsic nonradiative recombination centers (NRCs). The room-temperature τNR of various n-type GaN samples increased with decreasing the concentration of divacancies composed of a Ga vacancy (VGa) and a N vacancy (VN), namely, VGaVN. The τNR value also increased with increasing the diffusion length of positrons, which is almost proportional to the inverse third root of the gross concentration of all point defects. The results indicate that major intrinsic NRC in n-type GaN is VGaVN. From the relationship between its concentration and τNR, its hole capture-cross-section is estimated to be about 7 × 10-14 cm2. Different from the case of 4H-SiC, the major NRCs in p-type and n-type GaN are different: the major NRCs in Mg-doped p-type GaN epilayers are assigned to multiple vacancies containing a VGa and two (or three) VNs, namely, VGa(VN)n (n = 2 or 3). The ion-implanted Mg-doped GaN films are found to contain larger size vacancy complexes such as (VGa)3(VN)3. In analogy with GaN, major NRCs in Al0.6Ga0.4N alloys are assigned to vacancy complexes containing an Al vacancy or a VGa.

Original languageEnglish
Article number161413
JournalJournal of Applied Physics
Issue number16
Publication statusPublished - 2018 Apr 28

ASJC Scopus subject areas

  • Physics and Astronomy(all)


Dive into the research topics of 'The origins and properties of intrinsic nonradiative recombination centers in wide bandgap GaN and AlGaN'. Together they form a unique fingerprint.

Cite this