Next-generation on-chip plasmonic tweezer with a built-in light source

We are proposing next-generation lab-on-a-chip plasmonic tweezers with a built-in optical source that can be activated electrically. The building block of these tweezers is composed of an Au/p+-InAs/p+-AlAs0.16Sb0.84 Schottky diode, with a circular air-hole opened in the Au layer. Under an appropriate forward bias, the interband optical transitions in InAs, acting as a built-in optical source that can excite the localized surface plasmons (LSPs) around the edge of the hole. Numerical simulations show that the LSPs mode penetrates a chamber that is filled with water and electrically isolated from the top gold layer, providing the gradient force components desired for trapping the target nanoparticles suspended in the water. Moreover, we show that tweezers with air-holes of radius 90 nm under an applied bias of −1.6 V, can trap polystyrene nanoparticles of radius as small as 93 nm. The proposed structure provides a new platform for developing the next-generation compact on-chip plasmonic tweezers with no need for any external optical pump.