High-performance, air-stable, p-channel WSe2 top-gate field-effect transistors (FETs) using a bilayer gate dielectric composed of high- and low-k dielectrics are reported. Using only a high-k Al2O3 as the top-gate dielectric generally degrades the electrical properties of p-channel WSe2, therefore, a thin fluoropolymer (Cytop) as a buffer layer to protect the 2D channel from high-k oxide forming is deposited. As a result, a top-gate-patterned 2D WSe2 FET is realized. The top-gate p-channel WSe2 FET demonstrates a high hole mobility of 100 cm2 V-1 s-1 and a ION/IOFF ratio > 107 at low gate voltages (VGS ca. -4 V) and a drain voltage (VDS) of -1 V on a glass substrate. Furthermore, the top-gate FET shows a very good stability in ambient air with a relative humidity of 45% for 7 days after device fabrication. Our approach of creating a high-k oxide/low-k organic bilayer dielectric is advantageous over single-layer high-k dielectrics for top-gate p-channel WSe2 FETs, which will lead the way toward future electronic nanodevices and their integration.
Bibliographical noteFunding Information:
The study has been supported by the 973 National Nature Science Foundation of People''s Republic of China (2011CB933500), and supported by the Fundamental Research Funds for the Central Universities, Southeast University (3290005416).
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics