Two-Dimensional Van Der Waals Hafnium Disulfide and Zirconium Oxide-Based Micro-Interdigitated Electrodes Transistors

There are indelible challenges related to transistor action and realization of emerging two-dimensional van der Waals (vdW) multilayer (2D $_{{\mathrm {ml}}}$ ) field-effect transistors (FETs), to the post silicon technology era. For scalability, a cost-effective large area ultrafine thin films interface and band alignment of multilayer channel material with compatible gate dielectric are essential. Here, 2D $_{{\mathrm {ml}}}$ hafnium disulfide (HfS2) and ZrO2 are employed as channel material and gate dielectric, respectively, and anticipated that vdW interaction of said structures entails the high-quality interface with trivial dangling bonds and defects caused by lattice mismatch. The investigated Al/ZrO2/HfS2/Al $_{\mu {\text{-IDE}}}$ FETs exhibit the subthreshold swing (SS) ~65 mV/dec, ${I}_{ \mathrm{\scriptscriptstyle ON}}/I_{ \mathrm{\scriptscriptstyle OFF}}$ ratio of ~104, transconductance of ~3.99 $\mu \text{S}$ , effective mobility of ~74 cm2/Vs at ${V}_{{\mathrm {gs}}}$ of 2 V, and leakage current density of ~33.8 nA/cm2 at ${V}_{{\mathrm {gs}}}$ of −1 V. Thus, the steep SS, sturdy current saturation, low-voltage operation (~3 V), and leakage current establish the potential candidature of HfS2 and ZrO2-based 2-D FETs for both conventional and ubiquitous electronics.