Unlocking high performance, ultra-low power van der waals transistors: towards back-end-of-line in- sensor machine vision

A photodetector device comprising:

• a substrate having a gate electrode and a gate dielectric layer disposed thereover;
• a source electrode and a drain electrode formed on the gate dielectric layer;
• and
• a channel comprising a van der Waals (vdW) heterojunction of MoS2 and WSe2 bridging the source electrode and the drain electrode, wherein the gate electrode is operably configured to modulate photocurrent in the channel, and the photodetector device exhibits gate-tunable responsivity for white light detection with ultra-low power dissipation.

A method of fabricating a field-effect transistor (FET) phototransistor, comprising:

• providing a substrate comprising a gate electrode and a gate dielectric layer disposed over the gate electrode;
• depositing a source electrode and a drain electrode on the gate dielectric layer;
• placing a channel layer over and in contact with the source electrode and the drain electrode to bridge the source electrode and the drain electrode, the channel layer being composed of at least one van der Waals (vdW) two-dimensional material;
• and
• subjecting the phototransistor to an anneal and heal treatment process comprising applying a thermal pulse to reduce device resistance and increase electronic coupling between the channel layer and the source electrode and drain electrode.