Regulation of Charge Carrier Dynamics in ZnO Microarchitecture-Based UV/Visible Photodetector via Photonic-Strain Induced Effects
Small 2018, 14, 1703044
Y. Purusothaman, N. Rao Alluri, A. Chandrasekhar, V. Vivekananthan, and Sang-Jae Kim*
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 (IPh) response, i.e., IPh/ZnO F-MW > IPh/ZnO CMS > IPh/ZnO MW. The unique structural alignment of ZnO F-MW has enhanced the IPh from 14.2 to 186, 221, 290 μA upon various light intensities such as 0 to 6, 11, 17 mW cm−2 at λ405 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 IPh 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 (ΦSB). 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.