TY - JOUR
T1 - Large electron capture-cross-section of the major nonradiative recombination centers in Mg-doped GaN epilayers grown on a GaN substrate
AU - Chichibu, S. F.
AU - Shima, K.
AU - Kojima, K.
AU - Takashima, S.
AU - Edo, M.
AU - Ueno, K.
AU - Ishibashi, S.
AU - Uedono, A.
N1 - Funding Information:
The authors thank T. Ohtomo for help with the PL experiments. This work was supported in part by the Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP) (funding agency: NEDO) and the research Programs of “Program for research and development of next-generation semiconductor to realize energy-saving society” and “Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials,” and JSPS KAKENHI (Grant Nos. JP16H06424 and JP16H06427) by MEXT, Japan.
Publisher Copyright:
© 2018 Author(s).
PY - 2018/5/21
Y1 - 2018/5/21
N2 - Complementary time-resolved photoluminescence and positron annihilation measurements were carried out at room temperature on Mg-doped p-type GaN homoepitaxial films for identifying the origin and estimating the electron capture-cross-section (σ n) of the major nonradiative recombination centers (NRCs). To eliminate any influence by threading dislocations, free-standing GaN substrates were used. In Mg-doped p-type GaN, defect complexes composed of a Ga-vacancy (VGa) and multiple N-vacancies (VNs), namely, VGa(VN)2 [or even VGa(VN)3], are identified as the major intrinsic NRCs. Different from the case of 4H-SiC, atomic structures of intrinsic NRCs in p-type and n-type GaN are different: VGaVN divacancies are the major NRCs in n-type GaN. The σ n value approximately the middle of 10-13 cm2 is obtained for VGa(VN)n, which is larger than the hole capture-cross-section (σp = 7 × 10-14 cm2) of VGaVN in n-type GaN. Combined with larger thermal velocity of an electron, minority carrier lifetime in Mg-doped GaN becomes much shorter than that of n-type GaN.
AB - Complementary time-resolved photoluminescence and positron annihilation measurements were carried out at room temperature on Mg-doped p-type GaN homoepitaxial films for identifying the origin and estimating the electron capture-cross-section (σ n) of the major nonradiative recombination centers (NRCs). To eliminate any influence by threading dislocations, free-standing GaN substrates were used. In Mg-doped p-type GaN, defect complexes composed of a Ga-vacancy (VGa) and multiple N-vacancies (VNs), namely, VGa(VN)2 [or even VGa(VN)3], are identified as the major intrinsic NRCs. Different from the case of 4H-SiC, atomic structures of intrinsic NRCs in p-type and n-type GaN are different: VGaVN divacancies are the major NRCs in n-type GaN. The σ n value approximately the middle of 10-13 cm2 is obtained for VGa(VN)n, which is larger than the hole capture-cross-section (σp = 7 × 10-14 cm2) of VGaVN in n-type GaN. Combined with larger thermal velocity of an electron, minority carrier lifetime in Mg-doped GaN becomes much shorter than that of n-type GaN.
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U2 - 10.1063/1.5030645
DO - 10.1063/1.5030645
M3 - Article
AN - SCOPUS:85047609920
VL - 112
JO - Applied Physics Letters
JF - Applied Physics Letters
SN - 0003-6951
IS - 21
M1 - 211901
ER -