Controlling piezoelectric response in semiconductor quantum dots via impulsive charge localization.

Tyagi, Pooja; Cooney, Ryan R; Sewall, Samuel L; Sagar, D M; Saari, Jonathan I; Kambhampati, Patanjali · Nano Lett · 2010

basic_science · Level V

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Abstract

By direct observation of coherent acoustic phonons, we demonstrate a novel extrinsic piezoelectric response in colloidal CdSe semiconductor quantum dots. This response is driven by the migration of charges to the surface of the quantum dot on a vibrationally impulsive time scale. Surface- and fluence-dependent studies reveal that the observed carrier capture based piezo response is controllable and is at least an order of magnitude larger than the intrinsic piezo response of wurtzite CdSe.