High-performance n-type thin-film transistor based on bilayer MXene/semiconductor with enhanced electrons transport

Interfacial engineering at the dielectric/semiconductor interface is highly crucial for fabricating organic field-effect transistors with high performance. In this study, a bilayer MXene/semiconductor configuration is introduced to fabricate a high-performance n-type transistor, where electrical charges are formed and modulated at the SiO2/semiconductor interface, and MXene nanosheets serve as the primary electrical charge channel due to their high mobility and long lateral size. The electrical performance is optimized by adjusting the degree of connectivity of the MXene nanosheets. The proposed MXene/poly{[N,N'-bis(2-octyl-do-decyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (N2200) transistors show boosted n-type characteristics, including a 100-fold increase in field-effect mobility, a large ON/OFF ratio of 104, and a small subthreshold swing of 0.65 V dec(-1), all of which are significantly improved compared with single-layer N2200 transistors. The high performance of the two-dimensional MXene nanochannel is due to its electronegativity and high mobility. The electronegativity significantly enhances electron transfer from N2200 to the MXene channel, where they are efficiently transported along the MXene channel. Interestingly, the MXene/p-type semiconductor transistors show suppressed p-type performance because of the highly negative MXene nanosheets. Additionally, the proposed bilayer MXene/n-type semiconductor configuration shows a good configuration generality and improved performance. These findings demonstrate the feasibility of fabricating high-performance n-type transistors using a bilayer MXene/semiconductor combination.