Voltage-switchable photocurrents in single-walled carbon nanotube-silicon junctions for analog and digital optoelectronics

摘要

Recent progress in silicon photonics1-8 has dramatically advanced the possible realization of heterogeneous logic circuits9,10. A variety of Boolean optoelectronic circuits have been proposed11-15. In this context, experimental investigation of logic operations with both optical and electrical inputs in chipintegrable devices is highly desirable. Here, we present a new kind of photodiode-based logic device using scalable heterojunctions of carbon nanotubes and silicon, the output currents of which can be manipulated completely by both optical and electrical inputs. This provides a novel platform for heterogeneous optoelectronic logic elements with voltage-switchable photocurrent responsivity of >1 AW~(-1), photovoltage responsivity of >13 10~5VW~(-1), electrical on/off ratios of >1×10~5 and optical on/off ratios of >1×10~4. To demonstrate their scalability, we fabricated a large array of photoactive elements on a centimetre-scale wafer. We also present bidirectional phototransistors and novel clock-triggerable logic elements such as a mixed optoelectronic AND gate, a 2-bit optoelectronic ADDER/OR gate and a 4-bit optoelectronic digital-to-analog converter.