High-performance TiO2 UV photodetectors with improved response time achieved through sol-gel synthesis and PDMS surface passivation

Abstract

In the pursuit of enhancing ultraviolet (UV) photodetector performance, we present an advanced optimization technique that utilizes polydimethylsiloxane (PDMS) coating on titanium dioxide (TiO₂) thin films. The native surface of titanium dioxide thin films is rich in oxygen vacancies, and these defects usually lead to carrier trapping resulting in prolonged retention time, which in turn affects the performance of the prepared detectors and makes them underperform. Our improvement effectively mitigates the atypical carrier recombination associated with surface defects by reducing them. Consequently, we have achieved a substantial boost in the performance metrics of our TiO₂ UV photodetector through the implementation of cutting-edge surface modification methods. This refinement has led to a striking reduction in the detector's rise time, plummeting from 17.10 s to a mere 1.80 s, and an equally impressive decrease in the fall time, shrinking from 10.56 s to just 1.58 s. Moreover, the responsiveness and detection rate have seen a remarkable increase, jumping from 790.78 A/W and 5.91 × 10¹³ Jones to an impressive 4.04 × 10³ A/W and 1.48 × 10¹⁵ Jones, respectively.