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Khan MA, Bermundo JP, Ishikawa Y, Ikenoue H, Fujikawa S, Matsuura E, Kashima Y, Maeda N, Jo M, Hirayama H. Impact of Mg level on lattice relaxation in a p-AlGaN hole source layer and attempting excimer laser annealing on p-AlGaN HSL of UVB emitters. NANOTECHNOLOGY 2021; 32:055702. [PMID: 33007768 DOI: 10.1088/1361-6528/abbddb] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mg-doped p-type semiconducting aluminium-gallium-nitride hole source layer (p-AlGaN HSL) materials are quite promising as a source of hole 'p' carriers for the ultraviolet-B (UVB) light-emitting diodes (LEDs) and laser diodes (LDs). However, the p-AlGaN HSL has a central issue of low hole injection due to poor activation of Mg atoms, and the presence of unwanted impurity contamination and the existence of a localized coherent state. Therefore, first the impact of the Mg level on the crystallinity, Al composition and relaxation conditions in the p-AlGaN HSL were studied. An increasing trend in the lattice-relaxation ratios with increasing Mg concentrations in the p-AlGaN HSL were observed. Ultimately, a 40%-60% relaxed and 1.4 μm thick p-AlGaN HSL structure with total threading dislocation densities (total-TDDs) of approximately ∼8-9 × 108 cm-2 was achieved, which almost matches our previous design of a 4 μm thick and 50% relaxed n-AlGaN electron source layer (ESL) with total-TDDs of approximately ∼7-8 × 108 cm-2. Subsequently, structurally a symmetric p-n junction for UVB emitters was accomplished. Finally, the influence of excimer laser annealing (ELA) on the activation of Mg concentration and on suppression of unwanted impurities as well as on the annihilation of the localized energy state in the p-AlGaN HSL were thoroughly investigated. ELA treatment suggested a reduced Ga-N bonding ratio and increased Ga-O, as well as Ga-Ga bonding ratios in the p-AlGaN HSL. After ELA treatment the localized coherent state was suppressed and, ultimately, the photoluminescence emission efficiency as well as conductivity were drastically improved in the p-AlGaN HSL. By using lightly polarized p-AlGaN HSL assisted by ELA treatment, quite low resistivity in p-type AlGaN HSL at room temperature (hole concentration is ∼2.6 × 1016 cm-3, the hole mobility is ∼9.6 cm2 V1 s-1 and the resistivity is ∼24.39 Ω. cm) were reported. ELA treatment has great potential for localized activation of p-AlGaN HSL as well as n- and p-electrodes on n-AlGaN and p-AlGaN contact layers during the flip-chip (FC) process in low operating UVB emitters, including UVB lasers.
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Affiliation(s)
- M Ajmal Khan
- RIKEN Cluster for Pioneering Research (CPR), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Center for Advanced Photonics (RAP), 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Juan Paolo Bermundo
- Division of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Yasuaki Ishikawa
- Division of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Hiroshi Ikenoue
- Department of Gigaphoton Next GLP, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Sachie Fujikawa
- RIKEN Cluster for Pioneering Research (CPR), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | | | - Noritoshi Maeda
- RIKEN Cluster for Pioneering Research (CPR), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Masafumi Jo
- RIKEN Cluster for Pioneering Research (CPR), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hideki Hirayama
- RIKEN Cluster for Pioneering Research (CPR), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Center for Advanced Photonics (RAP), 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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Michałowski PP, Złotnik S, Sitek J, Rosiński K, Rudziński M. Oxygen-induced high diffusion rate of magnesium dopants in GaN/AlGaN based UV LED heterostructures. Phys Chem Chem Phys 2018; 20:13890-13895. [DOI: 10.1039/c8cp01470a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxygen breaks up Mg–H complexes and induces high diffusion of Mg in GaN/AlGaN heterostructures.
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Affiliation(s)
| | | | - Jakub Sitek
- Institute of Electronic Materials Technology
- 01-919 Warsaw
- Poland
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