Characterization of Nanowire Photodetectors

The funding of DURIP instrumentation proposal has enabled expansion of the electrical measurement capability in nanowires. Low frequency noise measurement has been set-up using the cross correlation technique. Successful demonstration of noise measurements on the single nanowire of different GaAsSb configurations, namely core-shell, Te-doped and PIN have been demonstrated. The temperature dependence measurement from 4K to 300K has also been demonstrated. The preliminary data obtained indicate the relaxation time for the generation-recombination mechanism to be within the range, 0.2 ms - 0.5 ms. It should be noted that these are preliminary data and require considerable improvement in both the suppression of the noise and mounting of the samples. This can be a powerful tool to provide more insight into the trap location and density in the GaAsSb NWs. The other equipment purchased from this funding, such as the addition of ultrafast I-V modules to the existing Keithley 4200 semiconductor characterization system and picosecond pulsed laser source will be used to provide deeper insight into the fast charge carrier dynamics in the GaAsSb and GaAsSbN nanowires, for potential applications in a wide range of optoelectronic devices at nanoscale.