Doping and Defect Engineering by Ions
Energetic ions interact with materials through electronic excitation, ionization, and nuclear collisions. These processes introduce dopant atoms and generate atomic displacements and lattice defects. The type, concentration, and depth distribution of impurities and defects can be precisely controlled through the ion species, energy, and fluence. Ion beams therefore provide a versatile approach to doping and defect engineering.
- Doping and defect engineering for 2D materials
- Hyperdoping for semiconductors
- Strain engineering
Doping and defect engineering for 2D materials
Reliable and controllable doping remains challenging for many 2D materials. Ion implantation followed by thermal annealing is the most established doping technology used in silicon-based nanoelectronics. Adapting implantation and annealing processes to 2D materials will enable controlled modification of their electrical properties—including n-type and p-type conductivity—as well as their optical and magnetic properties.
Related Publications
[1] Rise and Fall of the Ferromagnetism in CrSBr Flakes by Non‐Magnetic Ion Irradiation, Fangchao Long, Yi Li, Yu Cheng, Kseniia Mosina, Ulrich Kentsch, Zdenek Sofer, Slawomir Prucnal, Manfred Helm, Shengqiang Zhou, Advanced Physical Research, 3, 2400053 (2024)
[2] Strong exciton-phonon coupling as a fingerprint of magnetic ordering in van der Waals layered CrSBr, K. Lin, X. Sun, F. Dirnberger, Y. Li, J. Qu, P. Wen, Z. Sofer, A. Söll, S. Winnerl, M. Helm, S. Zhou, Y. Dan, S. Prucnal, ACS Nano 18, 2898-2905 (2024), arXiv:2308.04895 (2023)
[3] Ferromagnetic interlayer coupling in CrSBr crystals irradiated by ions F. Long, M. Ghorbani-Asl, K. Mosina, Y. Li, K. Lin, F. Ganss, R. Hübner, Z. Sofer, F. Dirnberger, A. Kamra, A. V. Krasheninnikov, S. Prucnal, M. Helm, S. Zhou Nano Lett. 23, 8468–8473 (2023)
[4] Chlorine doping of MoSe2 flakes by ion implantation S. Prucnal, A. Hashemi, M. Ghorbani Asl, R. Hübner, J. Duan, Y. Wei, D. Sharma, D. R. T. Zahn, R. Ziegenrücker, U. Kentsch, A. Krasheninnikov, M. Helm, S. Zhou Nanoscale 13, 5834 (2021)
Hyperdoping for semiconductors
emiconductor hyperdoping involves introducing dopant concentrations far above their equilibrium solubility limits. This can be achieved through ion implantation followed by pulsed-laser melting or flash lamp annealing. At sufficiently high concentrations, discrete dopant states overlap to form an impurity or intermediate band, giving rise to new electronic and optical properties. We have demonstrated that selenium- or tellurium-hyperdoped silicon is promising for silicon-based short-wave infrared photodetectors, while gallium-hyperdoped germanium can exhibit superconductivity.
Related Publications
[1] Dual-band plasmonic resonance-enhanced absorptance in Au/Si:Te heterostructures for mid-infrared applications, S. Peng, A. Wang, M. S. Shaikh, R. Hübner, T. Wang, M. Yuan, R. Heller, U. Kentsch, Y. Huang, J. Zhu, M. Tian, L. Li, S. Zhou, F. Chen, M. Wang, Applied Physics Letters 127, 191908 (2025)
[2] Superconductivity in Ga-doped SixGe1−x alloys through ion implantation and flash-lamp annealing, Y. Cheng, Y. Li, W. Mao, L. KuoChih, O. Steuer, X. K. Yue, R. Hübner, F. Ganss, A. Erbe, M. Helm, S. Zhou, S. Prucnal, Semiconductor Science and Technology 40, 065009 (2025)
[3] Charge transport in n-type As- and Sb-hyperdoped Ge, Mao Wang, M. S. Shaikh, Yi Li, S. Prucnal, J. Zuk, M. Turek, A. Drozdziel, K. Pyszniak, L. Rebohle, U. Kentsch, M. Helm, Shengqiang Zhou, Appl. Phys. Lett. 124, 142107 (2024)
[4] Mid- and far-infrared localized surface plasmon resonances in chalcogen-hyperdoped silicon, M. Wang, Y. Yu, S. Prucnal, Y. Berencén, M. Shaikh, L. Rebohle, M. B. Khan, V. Zviagin, R. Hübner, A. Pashkin, A. Erbe, Y. M. Georgiev, M. Grundmann, M. Helm, R. Kirchner and S. Zhou, Nanoscale 14, 2826 (2022)
[5] Breaking the doping limit in silicon by deep impurities, Mao Wang, A. Debernardi, Y. Berencén, R. Heller, Chi Xu, Ye Yuan, Yufang Xie, R. Böttger, L. Rebohle, W. Skorupa, M. Helm, S. Prucnal, Shengqiang Zhou, Phys. Rev. Applied 11, 054039 (2019) | arXiv:1809.06055
Strain engineering for oxides
Ion irradiation has emerged as a powerful tool for the efficient control of single-axis lattice expansion in order to fine tune and modulate the otherwise inaccessible complex correlated phases in oxide thin films. We have investigated the fine tuning of the magnetic moment as well as ferromagnetic-paramagnetic and metal-insulator transition temperatures in the NiCo2O4 inverse-spinel oxide by creating oxygen deficiencies caused by high energy He-ion irradiation. Tailoring of oxygen vacancies and consequently a uniaxial tensile strain drives the system towards the colossal increase of the magnetic moment by two-times. The results are corroborated well by spin-polarized electronic structure calculations with density functional theory and X-ray absorption spectroscopic data which show a peak height change and an energy shift of Co-L2,3 and Ni-L2,3 edges driven by the oxygen vacancies. Therefore, a new pathway via ion irradiation can be established to design new functionalities in other complex oxide thin films.
Cooperation partners
(1) Prof. Ying-Hao Chu
National Chao Tung University, Taiwan, ROC
(2) Prof. Deyang Chen
South China Normal University, PRC
Related Publications
[1] Modulating oxide-based quantum materials by ion implantation, A. Herklotz, T. Z. Ward, S. Zhou, Advanced Functional Materials 35(43), 2506647 (2025)
[2] In-plane charged antiphase boundary and 180° domain wall in a ferroelectric film
X. Cai, C. Chen, L. Xie, C. Wang, Z. Gui, Y. Gao, U. Kentsch, G. Zhou, X. Gao, Y. Chen, S. Zhou, W. Gao, J.-M. Liu, Y. Zhu, D. Chen
Nature Communications 14, 8174 (2023)
[3] Topological Hall effect in single thick SrRuO3 layers induced by defect engineering
C. Wang, C.-H. Chang, A. Herklotz, C. Chen, F. Ganss, U. Kentsch, D. Chen, X. Gao, Y.-J. Zeng, O. Hellwig, M. Helm, S. Gemming, Y.-H. Chu, S. Zhou
Advanced Electronic Materials 6, 2000184 (2020)
[4] Tunable disorder and localization in the rare-earth nickelates
Changan Wang, C.-H. Chang, A. Huang, P.-C. Wang, P.-C. Wu, L. Yang, Chi Xu, Parul Pandey, M. Zeng, Roman Böttger, H.-T. Jeng, Y.-J. Zeng, Manfred Helm, Y.-H. Chu, R. Ganesh, Shengqiang Zhou
Physical Review Materials 3, 053801 (2019)
[5] Controllable defect driven symmetry change and domain structure evolution in BiFeO3 with enhanced tetragonality
C. Chen, C. Wang, X. Cai, C. Xu, C. Li, J. Zhou, Z. Luo, Z. Fan, M. Qin, M. Zeng, X. Lu, X. Gao, U. Kentsch, P. Yang, G. Zhou, N. Wang, Y. Zhu, S. Zhou, D. Chen, J. Liu
Nanoscale 11, 8110-8118 (2019)
[6] Defect-induced exchange bias in a single SrRuO3 laye
C. Wang, C. Chen, C.-H. Chang, H.-S. Tsai, P. Pandey, C. Xu, R. Böttger, D. Chen, Y.-J. Zeng, X. Gao, M. Helm, S. Zhou
ACS Applied Materials and Interfaces 10, 27472-27476 (2018)
DOI: 10.1021/acsami.8b07918
[7] Enhancing the Magnetic Moment of Ferrimagnetic NiCo2O4 via Ion Irradiation driven Oxygen Vacancies
P. Pandey, Y. Bitla, M. Zschornak, M. Wang, C. Xu, J. Grenzer, D. C. Meyer, Y. Y. Chin, H. J. Lin, C. T. Chen, S. Gemming, M. Helm, Y. H. Chu, S. Zhou
APL Materials 6, 066109 (2018)
DOI: 10.1063/1.5036941
