Flexible Piezotronic Devices with Heterojunctions of 2D-Materials*

Integrated sensor systems capable of detecting multiple physical parameters are important for application in wireless sensor networks, IoT (Internet of Things), wearable sensors, bio-implantable devices etc. 2D materials with inherent piezoelectric properties are an excellent candidate for such piezotronics devices. The electrical properties of these devices can be tuned using the inherent piezoelectric response. A heterojunction formed with piezotronics material can be used for improved strain sensing and also achieve switching behaviour. These are advantageous compared to simple resistive configuration devices in terms of better control over the charge carrier movement and switching action. The efficient design of these devices can make them self-powered. We have fabricated lateral heterostructures of MoS₂ with other 2D materials such as MoTe₂ and WSe₂ on flexible substrates. We demonstrate the diode characteristics and response of these devices due to the strain. This study can be used to develop the stain gated transistors with heterojunctions of 2D materials.