Intrinsic n- and p-Type MgZnO Nanorods for Deep-UV Detection and Room-Temperature Gas Sensing

MgZnO (MZO) family, like other ternary compounds, offering tunable energy bandgap covering from blue to deep UV emission has attracted attentions for new optoelectronics, where both n- and p-types are essential. Nevertheless, only limited success is reported for p-type only by extrinsic doing. In the work, intrinsic n- and p-type single-crystalline MZO nanorods (NRs) were synthesized using a low-cost multistep process via the solid-state diffusion of Mg into intrinsic n- and p-type ZnO NRs prepared using chemical bath deposition or chemical vapor deposition. Cathodoluminescence spectra demonstrate substantial blue-shifted ultraviolet (UV) emission from 377 to 357 nm for MZO NRs with the highest Mg content. Photosensing measurements of the MZO NR devices show high sensitivity to UVC compared to UVA with bias-dependent sensitivity. Room-temperature gas sensing using MZO NRs exhibits enhanced sensitivity compared to that for ZnO, with opposite responses in current variation, supporting different carrier types of MZO NRs. The synthesis mechanisms of p/n MZO NRs and carrier-type-dependent sensing mechanisms were proposed. The n- and p-type MZO NRs are useful for fabricating multifunctional nanodevices.