Devices               Batteries               Electrocatalysis               Material Design

Our research explores atomically thin 2D materials for energy efficient devices in next generation information and communication technologies. We are particularly interested in achieving ideal contacts to 2D semiconductors that would help reap the benefits of short channel devices. Our demonstration of phase engineered contacts in 2D Transition metal dichalcogenides and van der Waals contacts between metals and monolayer semiconductors have been key milestones in this direction. We are currently using these ideal contacts to improve the injection of carriers (both charge and spin) in devices that rely on tunneling, for both logic and memory devices. We are also interested in understanding the fundamental mechanisms by which 2D materials interact with functional oxides where interfacial coupling between various degrees of freedom could lead to quantum electronic and optical phenomena. 

Articles from the Group

Toward Ideal Electrical Contacts for 2D Semiconductors

The contact between metals and semiconductors is the foundation of modern-day electronics. The dimensions of electronics have decreased to the point where bulk semiconductor-based transistors experience high off state currents – leading to heat and power dissipation in devices. Two-dimensional (2D) semiconductors that are atomically thin can mitigate these concerns in short channel transistors. However, to reap the benefits of 2D semiconductors, contact resistance must be reduced down to the quantum limit. 

Our group achieved a breakthrough in 2014 by using phase engineering to realize low contact resistance contacts on few-layered MoS₂ (Nature Materials 13, 1128, 2014).

Recently, we have demonstrated controlled creation of ultra-clean van der Waals electrical contacts between three-dimensional (3D) indium metal and atomically thin two-dimensional (2D) semiconductors. Unlike other metals that damage the atomically thin semiconductors due to kinetic energy transfer and/or chemical reactions, we have discovered the gentle low temperature deposition of soft indium metal by thermal evaporation leads to pristine undamaged interfaces (See Figure below and Nature 568, 70 – 74, 2019). Such ultra-clean metal-semiconductor interfaces are one essential parameter for realizing high performance electronics with 2D semiconductors.