Interface engineering for high-efficiency spin injection and polarized emission in GaN-based devices

Qihong Lai; Weilin Hu; Mingyu Chen; Hongshu Li; Ying Ye; Guimin Liao; Jian Huang; Xuanli Zheng; Lijing Kong; Yaping Wu; Xu Li; Zhiming Wu; Junyong Kang

doi:10.1088/1674-4926/25120016

J. Semicond. > Just Accepted

ARTICLES

Interface engineering for high-efficiency spin injection and polarized emission in GaN-based devices

Qihong Lai^§, Weilin Hu^§, Mingyu Chen, Hongshu Li, Ying Ye, Guimin Liao, Jian Huang, Xuanli Zheng, Lijing Kong, Yaping Wu, Xu Li, Zhiming Wu and Junyong Kang

+ Author Affiliations

Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People’s Republic of China
^§Qihong Lai and Weilin Hu contributed equally to this work and should be considered as co-first authors.

Author Bio:

Qihong Lai received his BS degree in Physics from Xiamen University in 2023. He is currently pursuing his MS degree at the School of Physics and Technology, Xiamen University, under the supervision of Prof. Zhiming Wu. His research focuses on spin injection in GaN-based devices and the application of two-dimensional materials in spintronic heterostructures.

Weilin Hu received her MS degree in Physics from Xiamen University in 2023. She graduated from the School of Physics and Technology, Xiamen University, under the supervision of Prof. Zhiming Wu. Her research focuses on spin injection in GaN-based devices.

Yaping Wu received her PhD degree in microelectronics and solid-state electronics from Xiamen University and is now a professor and doctoral supervisor at the Department of Physics Xiamen University. She has long been dedicated to the research of new structural materials and new functional devices, including wide-bandgap semiconductor optoelectronic devices, quantum structures and devices, and spintronics.

Xu Li received his PhD degree in Electrical and Electronic Engineering from the University of Hong Kong in 2017, and his MS and BS degrees from the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, and Zhejiang University in 2013 and 2010, respectively. He is currently a professor at the School of Physics and Technology, Xiamen University. His research focuses on semiconductor materials and devices, optoelectronic devices, magnetic materials, and spintronic devices.

Zhiming Wu received his PhD degree in Physics from East China Normal University in 2007. He is currently a professor at the School of Physics and Technology, Xiamen University. From 2015 to 2016, he was a visiting scholar at Oak Ridge National Laboratory, USA. His research focuses on semiconductor materials and devices, particularly spin optoelectronic devices.

Corresponding author: Yaping Wu, ypwu@xmu.edu.cn; Xu Li, xuliphys@xmu.edu.cn; Zhiming Wu, zmwu@xmu.edu.cn

DOI: 10.1088/1674-4926/25120016CSTR: 32376.14.1674-4926.25120016

Abstract: Efficient spin injection is crucial for developing high-performance spintronic and optoelectronic devices. To address the issue of low spin injection efficiency caused by lattice mismatch and interface defects in traditional CoFeB/MgO tunnel junctions, this work proposes a strategy of using graphene as an insertion layer to optimize interface quality and enhance the spin injection efficiency of tunnel junctions. By systematically investigating three types of tunnel junction structures, namely CoFeB/MgO, CoFeB/Graphene/MgO and CoFeB/MgO/Graphene, we demonstrate that the graphene insertion layer can effectively release interface stress, reduce defects and distortions induced by lattice mismatch, and thereby suppress spin scattering. Meanwhile, it alleviates resistance mismatch while preserving high spin polarization. Ultimately, the spin injection polarization is increased from 10.6% to 16.2%, representing an enhancement of approximately 53%. Additionally, the optimized CoFeB/MgO/Graphene tunnel junction was integrated into GaN-based spin light-emitting diodes, resulting in an increased circular polarization of electroluminescence from 8.4% to 17.3%. This work provides an interface engineering strategy for achieving efficient spin injection and advancing the development of spin-optoelectronic devices.

Key words: spin injection, tunnel junction, graphene, III-nitride semiconductors, spin light-emitting diodes

References

[1]	Incorvia J A C, Xiao T P, Zogbi N, et al. Spintronics for achieving system-level energy-efficient logic. Nat Rev Electr Eng, 2024, 1(11): 700 doi: 10.1038/s44287-024-00103-z
[2]	Liu T J, Huang Y Q. Circularly polarized electroluminescence from light-emitting diodes: Mechanisms, materials, and applications. J Mater Chem C, 2025, 13(35): 17996 doi: 10.1039/D5TC02301G
[3]	Nishizawa N, Munekata H. Lateral-type spin-photonics devices: Development and applications. Micromachines, 2021, 12(6): 644 doi: 10.3390/mi12060644
[4]	Hirohata A, Yamada K, Nakatani Y, et al. Review on spintronics: Principles and device applications. J Magn Magn Mater, 2020, 509: 166711 doi: 10.1016/j.jmmm.2020.166711
[5]	Igarashi J, Jinnai B, Watanabe K, et al. Single-nanometer CoFeB/MgO magnetic tunnel junctions with high-retention and high-speed capabilities. npj Spintron, 2024, 2: 1 doi: 10.1038/s44306-023-00003-2
[6]	Lee D, Raghunathan S, Wilson R J, et al. The influence of Fermi level pinning/depinning on the Schottky barrier height and contact resistance in Ge/CoFeB and Ge/MgO/CoFeB structures. Appl Phys Lett, 2010, 96(5): 052514 doi: 10.1063/1.3285163
[7]	Wu X F, Li X, Kang W Y, et al. Topology-induced chiral photon emission from a large-scale meron lattice. Nat Electron, 2023, 6(7): 516 doi: 10.1038/s41928-023-00990-4
[8]	Xie Y F, Zhang S Y, Yin Y, et al. Emerging ferromagnetic materials for electrical spin injection: Towards semiconductor spintronics. npj Spintron, 2025, 3: 10 doi: 10.1038/s44306-024-00070-z
[9]	Lukyanenko A V, Shanidze L V, Rautskii M V, et al. Magnetoresistive effect in vertical Fe₃Si/Ge/Mn₅Ge3/Si(111) hybrid structures. Bull Russ Acad Sci Phys, 2024, 88(S1): S42 doi: 10.1134/S1062873824708766
[10]	Zhang X Y, Tang N, Yang L Y, et al. Electrical spin injection into the 2D electron gas in AlN/GaN heterostructures with ultrathin AlN tunnel barrier. Adv Funct Mater, 2021, 31(15): 2009771 doi: 10.1002/adfm.202009771
[11]	Chen M Y, Huang S M, Jiang W, et al. High-efficient spin injection in GaN through a lattice-matched tunnel layer. Appl Phys Lett, 2024, 124(24): 242401 doi: 10.1063/5.0194999
[12]	Liu Z T, Liu B Y, Chen Z L, et al. Two-dimensional material-assisted remote epitaxy and van der Waals epitaxy: A review. Natl Sci Open, 2023, 2(4): 20220068 doi: 10.1360/nso/20220068
[13]	Kim J, Bayram C, Park H, et al. Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene. Nat Commun, 2014, 5: 4836 doi: 10.1038/ncomms5836
[14]	Bae S H, Lu K Y, Han Y M, et al. Graphene-assisted spontaneous relaxation towards dislocation-free heteroepitaxy. Nat Nanotechnol, 2020, 15(4): 272 doi: 10.1038/s41565-020-0633-5
[15]	Kobayashi Y, Kumakura K, Akasaka T, et al. Layered boron nitride as a release layer for mechanical transfer of GaN-based devices. Nature, 2012, 484(7393): 223 doi: 10.1038/nature10970
[16]	Shi B, Liu Z T, Li Y, et al. Atomic evolution mechanism and suppression of edge threading dislocations in nitride remote heteroepitaxy. Nano Lett, 2024, 24(24): 7458 doi: 10.1021/acs.nanolett.4c01724
[17]	An L P, Liu N H. First-principles study on transport properties of zigzag graphene nanoribbon with different spin-configurations. J Semicond, 2011, 32(5): 052001 doi: 10.1088/1674-4926/32/5/052001
[18]	Lu H C, Guo Y Z, Robertson J. Ab initio study of hexagonal boron nitride as the tunnel barrier in magnetic tunnel junctions. ACS Appl Mater Interfaces, 2021, 13(39): 47226 doi: 10.1021/acsami.1c13583
[19]	Lu H, Robertson J, Naganuma H. Comparison of hexagonal boron nitride and MgO tunnel barriers in Fe, Co magnetic tunnel junctions. Appl Phys Rev, 2021, 8(3): 031307 doi: 10.1063/5.0049792
[20]	Novoselov K S, Geim A K, Morozov S V, et al. Electric field effect in atomically thin carbon films. Science, 2004, 306(5696): 666 doi: 10.1126/science.1102896
[21]	Bolotin K I, Sikes K J, Jiang Z, et al. Ultrahigh electron mobility in suspended graphene. Solid State Commun, 2008, 146(9-10): 351 doi: 10.1016/j.ssc.2008.02.024
[22]	Sarkar S, Oh S, Newton P J, et al. Spin injection in graphene using ferromagnetic van der Waals contacts of indium and cobalt. Nat Electron, 2025, 8(3): 215 doi: 10.1038/s41928-024-01330-w
[23]	Al-Mumen H, Rao F B, Li W, et al. Singular sheet etching of graphene with oxygen plasma. Nano-Micro Lett, 2014, 6(2): 116 doi: 10.1007/BF03353775
[24]	Wang Z, Shan X Y, Cui X G, et al. Characteristics and techniques of GaN-based micro-LEDs for application in next-generation display. J Semicond, 2020, 41(4): 041606 doi: 10.1088/1674-4926/41/4/041606
[25]	Wei Y P, Wu Y P. Electrically switchable helicity of light driven by the spin-orbit torque effect. J Semicond, 2024, 45(11): 110402 doi: 10.1088/1674-4926/24080048
[26]	Sun Z H, Tang N, Chen S Y, et al. Spin injection into heavily-doped n-GaN via Schottky barrier. J Semicond, 2023, 44(8): 082501 doi: 10.1088/1674-4926/44/8/082501
[27]	Hindmarch A T, Dempsey K J, Ciudad D, et al. Fe diffusion, oxidation, and reduction at the CoFeB/MgO interface studied by soft X-ray absorption spectroscopy and magnetic circular dichroism. Appl Phys Lett, 2010, 96(9): 092501 doi: 10.1063/1.3332576
[28]	Lu Y, Lépine B, Jézéquel G, et al. Depth analysis of boron diffusion in MgO/CoFeB bilayer by X-ray photoelectron spectroscopy. J Appl Phys, 2010, 108(4): 043703 doi: 10.1063/1.3465308
[29]	Bunch J S, Verbridge S S, Alden J S, et al. Impermeable atomic membranes from graphene sheets. Nano Lett, 2008, 8(8): 2458 doi: 10.1021/nl801457b
[30]	Hong J, Lee S, Lee S, et al. Graphene as an atomically thin barrier to Cu diffusion into Si. Nanoscale, 2014, 6(13): 7503 doi: 10.1039/C3NR06771H
[31]	Jansen R. Silicon spintronics. Nat Mater, 2012, 11(5): 400 doi: 10.1038/nmat3293
[32]	Tombros N, Jozsa C, Popinciuc M, et al. Electronic spin transport and spin precession in single graphene layers at room temperature. Nature, 2007, 448(7153): 571 doi: 10.1038/nature06037
[33]	Dash S P, Sharma S, Patel R S, et al. Electrical creation of spin polarization in silicon at room temperature. Nature, 2009, 462(7272): 491 doi: 10.1038/nature08570
[34]	Jedema F J, Costache M V, Heersche H B, et al. Electrical detection of spin accumulation and spin precession at room temperature in metallic spin valves. Appl Phys Lett, 2002, 81(27): 5162 doi: 10.1063/1.1532753
[35]	Gurram M, Omar S, van Wees B J. Bias induced up to 100% spin-injection and detection polarizations in ferromagnet/bilayer-hBN/graphene/hBN heterostructures. Nat Commun, 2017, 8: 248 doi: 10.1038/s41467-017-00317-w
[36]	Giba A E, Gao X, Stoffel M, et al. Spin injection and relaxation in p-doped (In, Ga)As/GaAs quantum-dot spin light-emitting diodes at zero magnetic field. Phys Rev Appl, 2020, 14(3): 034017 doi: 10.1103/PhysRevApplied.14.034017
[37]	Holub M, Bhattacharya P. Spin-polarized light-emitting diodes and lasers. J Phys D: Appl Phys, 2007, 40(11): R179 doi: 10.1088/0022-3727/40/11/R01
[38]	Yu J D, Wang L, Yang D, et al. Study on spin and optical polarization in a coupled InGaN/GaN quantum well and quantum dots structure. Sci Rep, 2016, 6: 35597 doi: 10.1038/srep35597

Fig. 1. (Color online) (a) Schematic illustration of three-terminal devices integrated with different structures of tunnel junctions: CoFeB/MgO, CoFeB/Graphene/MgO, and CoFeB/MgO/Graphene. (b) Optical microscope image of a typical device. (c) Hanle signals of the different three-terminal devices at an injection current of 5.0 μA.

DownLoad: Full-Size Img PowerPoint

Fig. 2. (Color online) (a) and (b) Cross-sectional TEM images of the CoFeB/MgO/GaN and CoFeB/MgO/Graphene/GaN interfaces, respectively; (c) and (d) Schematics of the tunneling mechanisms for the device I and device III, respectively.

DownLoad: Full-Size Img PowerPoint

Fig. 3. (Color online) (a) Schematic illustration of a four-terminal spin-injection device with an MgO tunnel junction (channel widths: 1500, 500, and 1000 nm); (b) schematic illustration of a device with an MgO/Graphene tunnel junction (channel widths: 1500, 500, and 1000 nm); insets in (a) and (b) display the optical microscope images of the corresponding devices; (c), (d) MR curves for the MgO and MgO/Graphene junction devices measured at a bias current of 10 μA.

DownLoad: Full-Size Img PowerPoint

Fig. 4. (Color online) (a) Schematic illustration of the spin-LED structure. (b) and (c) Spin-resolved edge-emission spectra of LED-I at 0 and 100 mT, respectively. (d) and (e) Spin-resolved edge-emission spectra of LED-II at 0 and 100 mT, respectively. The symbols represent the raw experimental data, and the solid lines represent the corresponding smoothed curves for visual guidance. The working current is 2 mA, and the applied magnetic field is aligned to the surface of LED.

DownLoad: Full-Size Img PowerPoint

Fig. 5. (Color online) (a) Hysteresis loop of the CoFeB injector and magnetic-field dependence of the circular polarization of the LED-II device. (b) Circular polarization of the LED-II with different working currents under 100 mT.

DownLoad: Full-Size Img PowerPoint

[1]	Incorvia J A C, Xiao T P, Zogbi N, et al. Spintronics for achieving system-level energy-efficient logic. Nat Rev Electr Eng, 2024, 1(11): 700 doi: 10.1038/s44287-024-00103-z
[2]	Liu T J, Huang Y Q. Circularly polarized electroluminescence from light-emitting diodes: Mechanisms, materials, and applications. J Mater Chem C, 2025, 13(35): 17996 doi: 10.1039/D5TC02301G
[3]	Nishizawa N, Munekata H. Lateral-type spin-photonics devices: Development and applications. Micromachines, 2021, 12(6): 644 doi: 10.3390/mi12060644
[4]	Hirohata A, Yamada K, Nakatani Y, et al. Review on spintronics: Principles and device applications. J Magn Magn Mater, 2020, 509: 166711 doi: 10.1016/j.jmmm.2020.166711
[5]	Igarashi J, Jinnai B, Watanabe K, et al. Single-nanometer CoFeB/MgO magnetic tunnel junctions with high-retention and high-speed capabilities. npj Spintron, 2024, 2: 1 doi: 10.1038/s44306-023-00003-2
[6]	Lee D, Raghunathan S, Wilson R J, et al. The influence of Fermi level pinning/depinning on the Schottky barrier height and contact resistance in Ge/CoFeB and Ge/MgO/CoFeB structures. Appl Phys Lett, 2010, 96(5): 052514 doi: 10.1063/1.3285163
[7]	Wu X F, Li X, Kang W Y, et al. Topology-induced chiral photon emission from a large-scale meron lattice. Nat Electron, 2023, 6(7): 516 doi: 10.1038/s41928-023-00990-4
[8]	Xie Y F, Zhang S Y, Yin Y, et al. Emerging ferromagnetic materials for electrical spin injection: Towards semiconductor spintronics. npj Spintron, 2025, 3: 10 doi: 10.1038/s44306-024-00070-z
[9]	Lukyanenko A V, Shanidze L V, Rautskii M V, et al. Magnetoresistive effect in vertical Fe₃Si/Ge/Mn₅Ge3/Si(111) hybrid structures. Bull Russ Acad Sci Phys, 2024, 88(S1): S42 doi: 10.1134/S1062873824708766
[10]	Zhang X Y, Tang N, Yang L Y, et al. Electrical spin injection into the 2D electron gas in AlN/GaN heterostructures with ultrathin AlN tunnel barrier. Adv Funct Mater, 2021, 31(15): 2009771 doi: 10.1002/adfm.202009771
[11]	Chen M Y, Huang S M, Jiang W, et al. High-efficient spin injection in GaN through a lattice-matched tunnel layer. Appl Phys Lett, 2024, 124(24): 242401 doi: 10.1063/5.0194999
[12]	Liu Z T, Liu B Y, Chen Z L, et al. Two-dimensional material-assisted remote epitaxy and van der Waals epitaxy: A review. Natl Sci Open, 2023, 2(4): 20220068 doi: 10.1360/nso/20220068
[13]	Kim J, Bayram C, Park H, et al. Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene. Nat Commun, 2014, 5: 4836 doi: 10.1038/ncomms5836
[14]	Bae S H, Lu K Y, Han Y M, et al. Graphene-assisted spontaneous relaxation towards dislocation-free heteroepitaxy. Nat Nanotechnol, 2020, 15(4): 272 doi: 10.1038/s41565-020-0633-5
[15]	Kobayashi Y, Kumakura K, Akasaka T, et al. Layered boron nitride as a release layer for mechanical transfer of GaN-based devices. Nature, 2012, 484(7393): 223 doi: 10.1038/nature10970
[16]	Shi B, Liu Z T, Li Y, et al. Atomic evolution mechanism and suppression of edge threading dislocations in nitride remote heteroepitaxy. Nano Lett, 2024, 24(24): 7458 doi: 10.1021/acs.nanolett.4c01724
[17]	An L P, Liu N H. First-principles study on transport properties of zigzag graphene nanoribbon with different spin-configurations. J Semicond, 2011, 32(5): 052001 doi: 10.1088/1674-4926/32/5/052001
[18]	Lu H C, Guo Y Z, Robertson J. Ab initio study of hexagonal boron nitride as the tunnel barrier in magnetic tunnel junctions. ACS Appl Mater Interfaces, 2021, 13(39): 47226 doi: 10.1021/acsami.1c13583
[19]	Lu H, Robertson J, Naganuma H. Comparison of hexagonal boron nitride and MgO tunnel barriers in Fe, Co magnetic tunnel junctions. Appl Phys Rev, 2021, 8(3): 031307 doi: 10.1063/5.0049792
[20]	Novoselov K S, Geim A K, Morozov S V, et al. Electric field effect in atomically thin carbon films. Science, 2004, 306(5696): 666 doi: 10.1126/science.1102896
[21]	Bolotin K I, Sikes K J, Jiang Z, et al. Ultrahigh electron mobility in suspended graphene. Solid State Commun, 2008, 146(9-10): 351 doi: 10.1016/j.ssc.2008.02.024
[22]	Sarkar S, Oh S, Newton P J, et al. Spin injection in graphene using ferromagnetic van der Waals contacts of indium and cobalt. Nat Electron, 2025, 8(3): 215 doi: 10.1038/s41928-024-01330-w
[23]	Al-Mumen H, Rao F B, Li W, et al. Singular sheet etching of graphene with oxygen plasma. Nano-Micro Lett, 2014, 6(2): 116 doi: 10.1007/BF03353775
[24]	Wang Z, Shan X Y, Cui X G, et al. Characteristics and techniques of GaN-based micro-LEDs for application in next-generation display. J Semicond, 2020, 41(4): 041606 doi: 10.1088/1674-4926/41/4/041606
[25]	Wei Y P, Wu Y P. Electrically switchable helicity of light driven by the spin-orbit torque effect. J Semicond, 2024, 45(11): 110402 doi: 10.1088/1674-4926/24080048
[26]	Sun Z H, Tang N, Chen S Y, et al. Spin injection into heavily-doped n-GaN via Schottky barrier. J Semicond, 2023, 44(8): 082501 doi: 10.1088/1674-4926/44/8/082501
[27]	Hindmarch A T, Dempsey K J, Ciudad D, et al. Fe diffusion, oxidation, and reduction at the CoFeB/MgO interface studied by soft X-ray absorption spectroscopy and magnetic circular dichroism. Appl Phys Lett, 2010, 96(9): 092501 doi: 10.1063/1.3332576
[28]	Lu Y, Lépine B, Jézéquel G, et al. Depth analysis of boron diffusion in MgO/CoFeB bilayer by X-ray photoelectron spectroscopy. J Appl Phys, 2010, 108(4): 043703 doi: 10.1063/1.3465308
[29]	Bunch J S, Verbridge S S, Alden J S, et al. Impermeable atomic membranes from graphene sheets. Nano Lett, 2008, 8(8): 2458 doi: 10.1021/nl801457b
[30]	Hong J, Lee S, Lee S, et al. Graphene as an atomically thin barrier to Cu diffusion into Si. Nanoscale, 2014, 6(13): 7503 doi: 10.1039/C3NR06771H
[31]	Jansen R. Silicon spintronics. Nat Mater, 2012, 11(5): 400 doi: 10.1038/nmat3293
[32]	Tombros N, Jozsa C, Popinciuc M, et al. Electronic spin transport and spin precession in single graphene layers at room temperature. Nature, 2007, 448(7153): 571 doi: 10.1038/nature06037
[33]	Dash S P, Sharma S, Patel R S, et al. Electrical creation of spin polarization in silicon at room temperature. Nature, 2009, 462(7272): 491 doi: 10.1038/nature08570
[34]	Jedema F J, Costache M V, Heersche H B, et al. Electrical detection of spin accumulation and spin precession at room temperature in metallic spin valves. Appl Phys Lett, 2002, 81(27): 5162 doi: 10.1063/1.1532753
[35]	Gurram M, Omar S, van Wees B J. Bias induced up to 100% spin-injection and detection polarizations in ferromagnet/bilayer-hBN/graphene/hBN heterostructures. Nat Commun, 2017, 8: 248 doi: 10.1038/s41467-017-00317-w
[36]	Giba A E, Gao X, Stoffel M, et al. Spin injection and relaxation in p-doped (In, Ga)As/GaAs quantum-dot spin light-emitting diodes at zero magnetic field. Phys Rev Appl, 2020, 14(3): 034017 doi: 10.1103/PhysRevApplied.14.034017
[37]	Holub M, Bhattacharya P. Spin-polarized light-emitting diodes and lasers. J Phys D: Appl Phys, 2007, 40(11): R179 doi: 10.1088/0022-3727/40/11/R01
[38]	Yu J D, Wang L, Yang D, et al. Study on spin and optical polarization in a coupled InGaN/GaN quantum well and quantum dots structure. Sci Rep, 2016, 6: 35597 doi: 10.1038/srep35597

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Received: 06 December 2025 Revised: 14 April 2026 Online: Accepted Manuscript: 26 May 2026

Article Navigation > Journal of Semiconductors > 2026 > Accepted Manuscript

Qihong Lai, Weilin Hu, Mingyu Chen, Hongshu Li, Ying Ye, Guimin Liao, Jian Huang, Xuanli Zheng, Lijing Kong, Yaping Wu, Xu Li, Zhiming Wu, Junyong Kang. Interface engineering for high-efficiency spin injection and polarized emission in GaN-based devices[J]. Journal of Semiconductors, 2026, In Press. doi: 10.1088/1674-4926/25120016 ****Q H Lai, W L Hu, M Y Chen, H S Li, Y Ye, G M Liao, J Huang, X L Zheng, L J Kong, Y P Wu, X Li, Z M Wu, and J Y Kang, Interface engineering for high-efficiency spin injection and polarized emission in GaN-based devices[J]. J. Semicond., 2026, accepted doi: 10.1088/1674-4926/25120016

Citation:

Q H Lai, W L Hu, M Y Chen, H S Li, Y Ye, G M Liao, J Huang, X L Zheng, L J Kong, Y P Wu, X Li, Z M Wu, and J Y Kang, Interface engineering for high-efficiency spin injection and polarized emission in GaN-based devices[J]. J. Semicond., 2026, accepted doi: 10.1088/1674-4926/25120016

Citation:

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Interface engineering for high-efficiency spin injection and polarized emission in GaN-based devices

DOI: 10.1088/1674-4926/25120016

CSTR: 32376.14.1674-4926.25120016

Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People’s Republic of China

More Information

Qihong Lai received his BS degree in Physics from Xiamen University in 2023. He is currently pursuing his MS degree at the School of Physics and Technology, Xiamen University, under the supervision of Prof. Zhiming Wu. His research focuses on spin injection in GaN-based devices and the application of two-dimensional materials in spintronic heterostructures
Weilin Hu received her MS degree in Physics from Xiamen University in 2023. She graduated from the School of Physics and Technology, Xiamen University, under the supervision of Prof. Zhiming Wu. Her research focuses on spin injection in GaN-based devices
Yaping Wu received her PhD degree in microelectronics and solid-state electronics from Xiamen University and is now a professor and doctoral supervisor at the Department of Physics Xiamen University. She has long been dedicated to the research of new structural materials and new functional devices, including wide-bandgap semiconductor optoelectronic devices, quantum structures and devices, and spintronics
Xu Li received his PhD degree in Electrical and Electronic Engineering from the University of Hong Kong in 2017, and his MS and BS degrees from the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, and Zhejiang University in 2013 and 2010, respectively. He is currently a professor at the School of Physics and Technology, Xiamen University. His research focuses on semiconductor materials and devices, optoelectronic devices, magnetic materials, and spintronic devices
Zhiming Wu received his PhD degree in Physics from East China Normal University in 2007. He is currently a professor at the School of Physics and Technology, Xiamen University. From 2015 to 2016, he was a visiting scholar at Oak Ridge National Laboratory, USA. His research focuses on semiconductor materials and devices, particularly spin optoelectronic devices
Corresponding author: ypwu@xmu.edu.cn; xuliphys@xmu.edu.cn; zmwu@xmu.edu.cn
Received Date: 2025-12-06
Revised Date: 2026-04-14

Available Online: 2026-05-26

Abstract

Abstract

Efficient spin injection is crucial for developing high-performance spintronic and optoelectronic devices. To address the issue of low spin injection efficiency caused by lattice mismatch and interface defects in traditional CoFeB/MgO tunnel junctions, this work proposes a strategy of using graphene as an insertion layer to optimize interface quality and enhance the spin injection efficiency of tunnel junctions. By systematically investigating three types of tunnel junction structures, namely CoFeB/MgO, CoFeB/Graphene/MgO and CoFeB/MgO/Graphene, we demonstrate that the graphene insertion layer can effectively release interface stress, reduce defects and distortions induced by lattice mismatch, and thereby suppress spin scattering. Meanwhile, it alleviates resistance mismatch while preserving high spin polarization. Ultimately, the spin injection polarization is increased from 10.6% to 16.2%, representing an enhancement of approximately 53%. Additionally, the optimized CoFeB/MgO/Graphene tunnel junction was integrated into GaN-based spin light-emitting diodes, resulting in an increased circular polarization of electroluminescence from 8.4% to 17.3%. This work provides an interface engineering strategy for achieving efficient spin injection and advancing the development of spin-optoelectronic devices.
- spin injection,
- tunnel junction,
- graphene,
- III-nitride semiconductors,
- spin light-emitting diodes

Supplementary materials to this article can be found online at.
^§Qihong Lai and Weilin Hu contributed equally to this work and should be considered as co-first authors.

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