Liquid water based optoelectronic computing chip

Abstract

Solid-state electronics have revolutionized modern society due to their exceptional computational capabilities. However, the power consumption of chips rises dramatically with increasing integration levels as post-treatment of individual computing unit cost. Here, we introduce a water computing chip with exceptionally low power consumption based on graphene/water/semiconductor photodetectors, which relies on a unique exponential decay of water molecule polarization transfer function (PTF) along the signal transmission direction. Through a designed Ising model to picture the dynamic polarization and depolarization process of water molecules between graphene and silicon, we illustrate a longitude decay PTF which guarantees low energy consumption for the pulse current output. Furthermore, the lateral decay PTF is verified by the realization of linearly superimposed currents in the diameter of centimeter scale based on 3*3 water photodetector array. The molecular dynamic simulations reveal the timescale of 25 femtosecond (fs) for one flip of single water molecule. Subsequently, the single logical operation only needs an ideal energy consumption up to attojoule (10-18 J). The decay of lateral PTF at the centimeter scale ensures the ability to fabricate water computing chips containing a large number of photodetector arrays under micro/nano fabrication technology, which mimics the numerous neural cells inside hippocampus. As a proof of concept, we show the capability for Multiply-Accumulate (MAC) computations using an 8*8 water computing chip by successfully identifying the ASCII code of ZJU. The water computing chips utilize naturally-sourced water and straightforward manufacturing techniques, which hold great potential in creating a chip similar with human brain.