Heterointerface-functionalized photoelectric response of metal-oxide schottky photodiode for intelligent fire detection

Ultraviolet photodetectors (UV-PDs) based on wide-bandgap oxide semiconductors (OSs) hold broad prospects in scientific, civil, and especially fire alarm applications. However, the hotly pursued flexible and hetero-integration capabilities are hindered by the high processing temperature of mainstream Ga₂O₃ UV-PDs, while the selective UV detection capability of low-temperature OS (LT-OS) is undermined by the pronounced contradictory effects of abundant native defects on electric and optoelectrical properties. Herein, a heterointerface-functionalized Schottky photodiode (HF-SPD) is proposed to realize high-performance LT-OS UV-PD. Due to the sophistically modulated Schottky contact and defect distribution, ultralow dark current and remarkable photoresponse are simultaneously achieved in In₂O₃ HF-SPDs. Under the typical 360-nm UV illumination, the responsivity (R) and detectivity (D^*) respectively reach 27.75 A W⁻¹ and 2.036 × 10¹³ Jones, enabling the early-fire-warning capability. Moreover, the HF-SPD possesses unique wavelength selectivity and bias-tunable photoelectrical characteristics. By feeding such multidimensional feature data into the multi-layer perceptron (MLP) neural network, the pattern recognition of the spectrum delivers a remarkable accuracy of 99.94%, ensuring the precise identification of combustion materials. Such an intelligent fire warning system demonstrates the prospects of algorithm-boosted LT-OS HF-SPDs in ubiquitous intelligent systems, such as wearable photodetection and in-sensor computing (ISC) devices.