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HL: Fachverband Halbleiterphysik

HL 18: 2D Materials and Heterostructures: Emerging Materials and Phenomena

HL 18.13: Talk

Tuesday, March 19, 2024, 12:45–13:00, EW 201

Oxidative chemical vapor deposition of highly conductive and transparent polymer layers for contact fabrication in 2D-MoS₂-based FET structures — •Jinmei Zhu^1,3, Florian Meierhofer¹, Marius Eckert^1,2, Stefan Wundrack², and Tobias Voss¹ — ¹Institute of Semiconductor Technology (IHT), TU Braunschweig, Braunschweig, Germany — ²Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany — ³Shijiazhuang College of Applied Technology, Shijiazhuang, China

For 2D MoS₂ field-effect transistors (FETs), contact fabrication easily results in damaging the MoS₂ channel due to the fragility of the atomically thin structure, making it difficult to reliably achieve high-performance devices. To overcome this challenge, the deposition of highly conductive and transparent polymer layers from the gas phase (oxidative chemical vapor deposition (oCVD)), is a promising approach that can lead to low-defect Ohmic contacts. In this work, we fabricated 2D MoS₂ bottom-gated FETs with poly (3, 4- ethylenedioxythiophene) (PEDOT) electrodes. PEDOT is a conductive polymer widely used as a transparent electrode material. We developed two contacting strategies to achieve a low-defect interface: in-situ oCVD electrode growth and electrode transfer method. By these means, we could pattern PEDOT layers and contact them onto MoS₂ channels without aggressive chemical and physical treatments. This allowed us to achieve low-defect MoS₂ channels with a clean and smooth interface of the PEDOT electrodes, significantly decreasing the charged impurity and interface-roughness scattering processes.

Keywords: 2D semiconductor; field-effect transistor; Ohmic contact; polymer electrode; contacting strategy