Minimizing Molecular-Dopant-Induced Disorder in Emerging Semiconductors

Doping has been one of the most essential methods to control charge carrier concentration in semiconductors. Excess generation of charge carriers is a key route for controlling electrical properties of semiconducting materials and typically accompanies alteration of electronic structure by the introduction of dopant impurities, both of which have played pivotal roles in making breakthroughs in inorganic microelectronic and optoelectronic devices both at research and industrial levels, especially for Si-based technology. Molecular doping is a facile and effective doping method for various semiconducting materials since it is relatively non-invasive compared to high-energy implantation of ionic impurities used in Si. However, there are main challenges remaining in fully utilising molecular doping in emerging semiconducting materials such as π-conjugated polymer semiconductors, two-dimensional materials and metal-halide perovskites due to the difficulties in preventing dopant-induced disorder effects while maintaining a high carrier mobility. This talk will introduce concepts that we have developed to minimizing the dopant-induced disorder [1, 2, 3] while mitigating current injection and doping stability issues in electronic devices [4, 5], and finally outline the future challenges remaining in the field to fully uncover the potentials.<br/><br/>[1] K. Kang, et. al., “2D Coherent Charge Transport in Highly Ordered Conducting Polymers Doped by Solid State Diffusion”, Nat. Mater., Vol. 15, p. 896, 2016.<br/>[2] J. Jang, et. al., “Reduced dopant-induced scattering in remote charge-transfer-doped MoS2 field-effect transistors”, Sci. Adv., Vol. 8, No. 38, p. eabn3181, 2022.<br/>[3] J. Lee, et. al., “Bulk Incorporation of Molecular Dopants into Ruddlesden–Popper Organic Metal–Halide Perovskites for Charge Transfer Doping”, Adv. Funct. Mater., doi:10.1002/adfm.202302048.<br/>[4] Y. Kim, et. al., “Enhanced Charge Injection Properties of Organic Field-Effect Transistor by Molecular Implantation Doping”, Adv. Mater., Vol. 31, p. 1806697, 2019.<br/>[5] Y. Kim, et. al., “Highly Stable Contact Doping in Organic Field Effect Transistors by Dopant-BlockadeMethod” Adv. Funct. Mater. (2020) Vol. 30, p. 2000058