Electronic coupling in InP nanoparticle arrays

Arrays and lattices formed from nanoparticles (NPs) present unique opportunities for new optoelectronic materials whose properties can be tuned by controlling the size of the individual NPs and their interparticle separation to effect strong inter-NP electronic coupling. Characterization of the interdot coupling as a function of interdot distance is essential. Using time-resolved THz spectroscopy, we report a six-fold increase in the transient photoconductivity in disordered arrays of 3.2 nm diameter InP NPs separated by 0.9 nm compared to arrays with 1.8 nm separation. Photoconductivity in the arrays is compared to that of isolated NPs and InP epilayers. The epilayer samples exhibit bulk transport behavior while the NP samples do not.