Regulation of Charge Carrier Dynamics in ZnO Microarchitecture-Based UV/Visible Photodetector via Photonic-Strain Induced Effects

A feasible, morphological influence on photoresponse behavior of ZnO microarchitectures such as microwire (MW), coral-like microstrip (CMS), fibril-like clustered microwire (F-MW) grown by one-step carrier gas/metal catalyst "free" vapor transport technique is reported. Among them, ZnO F-MW exhibits higher photocurrent (I_Ph ) response, i.e., I_{Ph/ZnO F-MW} > I_{Ph/ZnO CMS} > I_{Ph/ZnO MW} . The unique structural alignment of ZnO F-MW has enhanced the I_Ph from 14.2 to 186, 221, 290 µA upon various light intensities such as 0 to 6, 11, 17 mW cm^-2 at λ_{405 nm} . Herein, the nature of the as-fabricated ZnO photodetector (PD) is also demonstrated modulated by tuning the inner crystals piezoelectric potential through the piezo-phototronic effect. The I_Ph response of PD decreases monotonically by introducing compressive strain along the length of the device, which is due to the synergistic effect between the induced piezoelectric polarization and photogenerated charge carriers across the metal-semiconductor interface. The current behavior observed at the two interfaces acting as the source (S) and drain (D) is carefully investigated by analyzing the Schottky barrier heights (Φ_SB ). This work can pave the way for the development of geometrically modified strain induced performances of PD to promote next generation self-powered optoelectronic integrated devices and switches.