Low dimensional semiconductor for electronic and optoelectronic device applications*

Low dimensional semiconducting materials such as colloidal quantum dots (QDs) and two-dimensional van der Waals (2D vdWs) atomic crystals are an emerging class of new materials that can provide important resources for future electronics and materials sciences due to their unique physical properties.
In the first part, we report on a new approach to fabricate PbS QD sensitized IGZO hybrid phototransistors for cost-effective NIR detection. The PbS QD can be functionalized directly onto the surface of the IGZO TFT to create a new bi-functional optoelectronic device: a gate-tunable, highly sensitive, and easily integrated NIR-sensing three-terminal phototransistor. In the second part, we report on a high performance MoS₂ and BP nanosheet based nonvolatile memory transistors with polymer ferroelectric top gate insulator. The MoS₂ ferroelectric field-effect transistor (FeFET) shows a highest linear electron mobility value of 175 cm²/Vs with a high on/off current ratio more than 10⁷, and memory window more than 15 V. Our BP ferroelectric FETs (FeFETs) also exhibit a clear memory window of 15 V and a highest linear mobility value of 1159 cm²V^-1s^-1 with a 10³ on/off current ratio at room temperature in ambient air.