Abstract:
Semiconductor quantum dots are attractive nanomaterials to be used in numerous
research areas and device fabrication such as detectors, light-emitting diodes,
transistors, and photovoltaic cells due to their unique optoelectronic properties. Tunable
energy gap by quantum confinement effect and multiple exciton generation are the most
important unique properties of the quantum dots. In this study, Cost - efficient PbS
quantum dot – based photoconductive type infrared (IR) detectors have been fabricated
and studied the effect of doping on the performance of PbS quantum dot
photoconductive IR detectors. PbS quantum dots were deposited on the electrode by
successive ionic layer adsorption and reaction (SILAR) technique. Best number of
SILAR cycle corresponding the maximum responsivity of the detector has been
optimized. In order to find the suitable dopant for the PbS quantum dots, same
concentration (3 mM) of Mn2+, Zn2+, Cu2+ and Ni2+ ions have been used separately.
Suitable doping concentration of the best dopant has been optimized. 3 mM Zn2+ –
doped PbS quantum dot photoconductive IR detector corresponding to 35 SILAR cycles
shows a highest responsivity of 11.6 µA W-1 under the illumination of 0.25 W with a
monochromatic radiation with the wavelength of 940 nm. Zn - doped PbS quantum dots
are the suitable candidates for low-cost IR photon detection.
