Stability of the CNHi Complex and the Blue Luminescence Band in GaN. Issue 12 (15th October 2021)

• Record Type: Journal Article
• Authors: Reshchikov, Michael Alexander; Andrieiev, Oleksandr; Vorobiov, Mykhailo; McEwen, Ben; Shahedipour-Sandvik, Shadi; Ye, Dexian; Demchenko, Denis O.
• Is Part Of: Physica status solidi. Volume 258:Issue 12(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-15
• Subjects: GaN -- photoluminescence -- point defects -- semiconductors -- thermal annealing; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.202100392
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : The dissociation of the CN Hi complex in GaN is studied in detail using photoluminescence measurements and first‐principles calculations. The blue luminescence (BL2) band with a maximum at 3.0 eV is caused by electron transitions from an excited state located at 0.02 eV below the conduction band to the ground state of the CN Hi donor with the 0/+ level 0.15 eV above the valence band. The dissociation releases hydrogen atom, and the remaining CN defect with the −/0 state at 0.92 eV above the valence band is responsible for the yellow band (YL1) with a maximum at about 2.2 eV. The dissociation of the CN Hi complex can be caused by the photoinduced defect reaction mechanism under UV illumination at low temperature (≈20 K), leading to the bleaching of the BL2 band and simultaneous rise in the YL1 band. The bleaching is reversible. Alternatively, the complex dissociates after annealing at temperatures above 600 °C. The activation energy of this process (3–4 eV, depending on the annealing geometry) corresponds to the removal of hydrogen from the sample and not to the dissociation of the complex itself. Abstract : The CN Hi complex in GaN causes the blue luminescence (BL2) band with a maximum at 3.0 eV in GaN. The complex dissociates when annealed in nitrogen ambient at temperatures above 600 °C, and the BL2 band disappears. The BL2 band restores after annealing in the H2 + N2 ambient. The complex dissociation also occurs at low temperatures under UV light.