Easily Processable Cu₂O/Si Self-Powered Photodetector Array for Image Sensing Applications

Abstract

The fabrication of a conventional photodetector array (PDA) involves complex photolithography technology for pixel isolation. An easy process is essential for the mass production of PDAs. This study explores a facile method of fabricating a PDA that comprises 4 × 4 p-Cu 2 O/n-Si photodiode cells. A solutionprocessed p-type Cu 2 O film is patterned by removing the UVshielded portion by immersing it in water. The efficient separation of electron/hole pairs at the Cu 2 O/Si interface enables selfpowered operation with a responsivity of 0.3 A/W and a fast response speed (∼10 ms). The PDA has relatively good uniformity and negligible variation between pixels. It records simple characters with a satisfactory resolution and exhibits negligible degradation over 3 months. The combination of self-powering characteristics, high reliability, and easy processability indicates that this PDA can be used for image sensing applications.

Realization of a self-powered Cu2O ozone gas sensor through the lateral photovoltaic effect

“…22 When the two Fermi levels are aligned, a built-in electrical field is created pointing from Cu 2 O to Si ( y -direction). 24 When the surface is illuminated, a large number of electron–hole pairs are generated in the p–n junction. Due to the existence of the built-in potential, the holes in Si move to the Cu 2 O layer, while the electrons in Cu 2 O transition to the Si substrate.…”

“…21 It shows many promising characteristics, such as low cost, nontoxicity, long diffusion length, and direct energy gap in the visible region, so it is widely used for solar cell and photodetector applications. [22][23][24] Moreover, Cu 2 O has been explored to find new functionalities of chemiresistive gas sensing for NO 2 , CO, H 2 S and ozone (O 3 ). 20,[25][26][27] Recently, a strong lateral photovoltaic effect (LPE) in a Cu 2 O film was observed and studied.…”

Self-Powered InGaZnO Ozone Gas Sensors Based on a Metal–Semiconductor–Metal Structure with Asymmetric Interdigitated Electrodes

“…Self-powered devices have gained popularity as a research focus due to their ability to generate and store energy independently, reducing the demand for external power sources. − Additionally, they offer the advantage of increased autonomy for extended operation in various working environments with fewer spatial restrictions, and easy integration into existing systems. − The most common self-powered devices are self-powered photodetectors, which operate based on the internal field at the p–n junction. , This vertical device configuration can be further leveraged to advance the development of self-powered gas sensors . The open-circuit voltage ( V oc ) generated through incident light harvesting in the p–n junction serves as a readout voltage. , Its magnitude varies depending on the concentration of target gases .…”

“…1−3 The most common self-powered devices are selfpowered photodetectors, which operate based on the internal field at the p−n junction. 4,5 This vertical device configuration can be further leveraged to advance the development of selfpowered gas sensors. 6 The open-circuit voltage (V oc ) generated through incident light harvesting in the p−n junction serves as a readout voltage.…”