Picosecond response times in GaAs/AlGaAs core/shell nanowire-based photodetectors

• Published in: Applied physics letters 2011-06, Vol.98 (24), p.241113-241113-3
• Main Authors: Gallo, Eric M., Chen, Guannan, Currie, Marc, McGuckin, Terrence, Prete, Paola, Lovergine, Nico, Nabet, Bahram, Spanier, Jonathan E.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.3600061

High-speed metal-semiconductor-metal (MSM) photodetectors based on Schottky-contacted core/shell GaAs/AlGaAs and bare GaAs nanowires were fabricated and characterized. The measured core/shell temporal response has a ∼ 10   ps full-width at half-maximum and an estimated corrected value less than 5 ps. The bare GaAs devices exhibit a slower response ( ∼ 35   ps ) along with a slow decaying persistent photocurrent ( ∼ 80   s ) . The core/shell devices exhibit significantly improved dc and high-speed performance over bare nanowires and comparable performance to planar MSM photodetectors. The picosecond temporal response, coupled with picoampere dark current, demonstrate the potential for core/shell nanowires in high-speed imaging arrays and on-chip optical interconnects.