Piezo-Phototronic Effect Modulated Deep UV Photodetector Based on ZnO-Ga₂O₃ Heterojuction Microwire

A strain modulated solar-blinded photodetector (PD) based on ZnO-Ga₂O₃ core–shell heterojuction microwire is developed. This PD is highly sensitive to deep UV light centered at 261 nm. It performs ultrahigh sensitivity and spectral selectivity, which can response to rare weak deep UV light (≈1.3 µw cm⁻²) and almost no response to visible light wavelength ranges. Moreover, by using the piezo-phototronic effect, the deep UV current response is enhanced to about three times under −0.042% static strain. This is a three way coupling effect among pizoelectric polarization, simiconductor properties, and optical excitation, which exists in noncentral symmetric wurtzite semiconductors such as ZnO, GaN, and CdS. By modulating the energy band diagrams and charge carriers in the junction area upon straining, the optoelectronic processes are regulated. The strain induced piezopotential modulates carrier transport in the heterostructure, which improves the response of the PD, with potential applications for health monitoring, smart systems, deep space exploration, and security communication.