Optimizing electrospinning-hydrothermal hybrid process based on Taguchi method for modulation of point defects in ZnO micro/nano arrays towards photoelectronic application

Unlike previous work generally adopting high temperature annealing (≥500 °C) to suppress defects in hydrothermal grown ZnO, this work suppressed ZnO defects by optimizing overall process parameters of low temperature electrospinning-hydrothermal hybrid process (≤300 °C) with Taguchi method and Analysis of Variance (ANOVA). Sum ratio of defect peaks to eigen peaks (SRDE) in room-temperature photoluminescence (PL) spectrum was proposed to evaluate defect conditions in 27 experiments (L₂₇ (3⁸)). With the optimal process, good crystal quality (SRDE = 0.31) was achieved at low temperature (200 °C), of which the SRDE decreased by 68.04% compared with the initial counterpart. Then confirmation experiment was conducted to validate the selected levels, and results of signal-to-noise ratio (SNR) showed good agreement with the predicted ones. Besides, the response time and recovery time of the ZnO photodetectors with optimal process were decreased by 72.5% and 79.3%, respectively, compared with the initial ones. This method can also be used to fabricate ZnO materials with other wanted defect features.