High-performance infrared photo-transistor based on SWCNT decorated with PbS nanoparticles

This paper presents a low-cost high-gain infrared photo-transistor based on a nano-heterostructure comprising of a single wall carbon nanotube (SWCNT) decorated with PbS nanoparticles (NPs). These structures are prepared using a solution based process with chemical bonding of PbS NPs on SWCNT walls. SWCNT act as an efficient electron transfer channel from PbS NPs to electrodes. By optimization the band alignment between PbS NPs and the SWCNTs fast transfer of electrons is achieved. Fabricated photo-transistor exhibits a relatively fast response with an enhanced sensitivity up to 35% under a laser illumination with a wavelength of 1550 nm and a power intensity of about 2 mW/cm2. Conversion from p-type to n-type operation is obtained by changing the polarity of the gate voltage. High gain, excellent on/off photo-current ratio and stable operation indicate potential application of SWCNT as a charge extraction strategy.