Nanoplatelets Bridging a Nanotrench: A New Architecture for Photodetectors with Increased Sensitivity

Interparticle charge hopping severely limits the integration, of colloidal nanocrystals-fims for optoelectronic device applications. We, propose he to overcome this problem by using high aspect ratio interconnects made wide electrodes separated by a few tens of namometers, distance matching, the size of :a single nanoplatelet. The semiconducting cdSe/CdS nanoplatelet Coupling with such electrodes allows an efficient electron hole pair dissociation despite, the large-binding, energy, of the exciton, resulting in optimal photocoriductance- responsivity. We report the highest responsnrity obtained so far for CdSe Colloidal material with values reaching kA.W-1,, corresponding to eight decades of enhancement compared to usual micrometer scaled architecture In addition, a decrease of 1 order of magnitude of the current noise is observed, revealing the reduced influenee,of the, surface traps on transport The nanotrench geometry provides top access to ion gel electrolyte gating allowing for a photoresponsive transistor with 10(4) on/off ratio. A simple analytical model reproduces the device behavior and underlines the key parameters related to its performance.