Improved performance of top-gated multilayer MoS2 transistors with channel fully encapsulated by Al2O3 dielectric

Multilayer two-dimensional molybdenum disulfide (MoS2) field-effect transistors with Al2O3 or HfO2 as top gate dielectric and bottom passivation layer have been comparatively studied. The top-gated MoS2 transistor with Al2O3 as both top gate dielectric and bottom passivation layer exhibits excellent electrical characteristics with an on-off ratio of ∼106, a subthreshold swing of 97 mV dec−1, a low interface-trap density of 1.66×1012 cm−2eV−1, and a high field-effect mobility of 105 cm2 V−1 s−1. All these should be attributed to superior interface quality between Al2O3 top gate dielectric and MoS2, and enhanced dielectric screening effect due to Al2O3 bottom passivation layer.