Multispectral UV Imaging on Capacitive CMOS Arrays Enabled by Solution-Processed Metal-Oxide Nanoparticles

Area of Science:

• Optoelectronics
• Semiconductor device physics
• Materials science

Background:

• Conventional ultraviolet (UV) imagers are expensive due to specialized semiconductor fabrication processes.
• Existing imagers often lack selectivity and multispectral capabilities for UV detection.

Purpose of the Study:

• To develop a cost-effective UV imager using standard complementary metal-oxide-semiconductor (CMOS) technology.
• To enable band-selective and multispectral UV detection with a novel capacitive sensing principle.

Main Methods:

• Fabrication of an imaging chip using standard 40 nm CMOS technology.
• Implementation of a capacitive operation principle utilizing a photodielectric effect in a functionalization layer.
• Use of solution-processed, wide-bandgap metal-oxide nanoparticles (ZnO, SnO2, Ga2O3) for the functionalization layer.

Main Results:

• Demonstration of UV detection via capacitance changes caused by UV light.
• Achieved band-selective detection across UV-A, UV-B, and UV-C spectral regions.
• Exhibited low noise-equivalent powers (17-138 fW Hz^-1/2) and inherent visible-blindness.

Conclusions:

• The capacitive-CMOS platform offers a route to reduced fabrication complexity for UV imagers.
• This technology enables selective and multispectral UV imaging.
• Potential for widespread implementation in consumer and specialized products.