Dual-Mode ZnO/SnSe Heterojunction Devices with Integrated Bipolar Response Photodetectors and Artificial...

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Optoelectronic synapse devices (OESDs) integrate light sensing, memory, and computing, advancing in-sensor computing.
• Human visual systems inspire OESDs for efficient information processing.

Purpose of the Study:

• To develop a dual-mode device integrating bipolar response photodetectors (PDs) and artificial optoelectronic synapses.
• To explore the conversion between PD and OESD functions by modulating light intensity.
• To demonstrate in-sensor computing capabilities, including logic functions.

Main Methods:

• Fabrication of ZnO/SnSe heterojunctions for dual-mode functionality.
• Characterization of device performance as both PDs and OESDs under varying light conditions.
• Investigation of photovoltaic and photothermoelectric effects for PD mode.
• Analysis of defect-dominant carrier trapping/de-trapping for synaptic behavior.

Main Results:

• The device functions as a PD with switchable current polarity based on laser wavelength and intensity, attributed to photovoltaic and photothermoelectric effects.
• As an OESD, the device exhibits synaptic plasticity (short/long-term) and learning behaviors at low light intensities.
• Demonstrated implementation of "AND" and "OR" logic functions via in-sensor computing.

Conclusions:

• A novel ZnO/SnSe heterojunction device achieves dual-mode operation as a photodetector and an optoelectronic synapse.
• The device exhibits versatile photonic synaptic characteristics and enables in-sensor computing with logic functions.
• This work provides a new pathway for creating complex functionalities within a single device for advanced computing applications.