Fabrication of a Large‐Area Al‐Doped ZnO Nanowire Array Photosensor with Enhanced Photoresponse by Straining

Abstract The photosensing properties of flexible large‐area nanowire (NW)‐based photosensors are enhanced via in situ Al doping and substrate straining. A method for efficiently making nanodevices incorporating laterally doped NWs is developed and the strain‐dependent photoresponse is investigated. Photosensors are fabricated by directly growing horizontal single‐crystalline Al‐doped ZnO NW arrays across Au microelectrodes patterned on a flexible SiO₂/steel substrate to enhance the transportation of carriers and the junction between NWs and electrodes. The Raman spectrum of the Al:ZnO NWs, which have an average diameter and maximum length of around 40 nm and 6.8 μm, respectively, shows an Al‐related peak at 651 cm⁻¹. The device shows excellent photosensing properties with a high ultraviolet/visible rejection ratio, as well as extremely high maximum photoresponsivity and sensitivity at a low bias. Increasing the tensile strain from 0 to 5.6% linearly enhances the photoresponsivity from 1.7 to 3.8 AW⁻¹ at a bias of 1 V, which is attributed to a decrease in the Schottky barrier height resulting from a piezo‐photonic effect. The high‐performance flexible NW device presented here has applications in coupling measurements of light and strain in a flexible photoelectronic nanodevice and can aid in the development of better flexible and integrated photoelectronic systems.