Miniaturizing Color-Sensitive Photodetectors via Hybrid Nanoantennas towards Sub-micron Dimensions

TL;DR

This paper introduces hybrid silicon-aluminum nanostructures that enable sub-micron pixel sizes in color-sensitive photodetectors, reducing optical cross-talk and enhancing sensor functionalities.

Contribution

It presents a novel hybrid nanostructure design supporting dual resonance for color selectivity and integrated charge separation, enabling ultra-high pixel density sensors.

Findings

Achieves sub-micron pixel dimensions

Reduces optical cross-talk in sensors

Supports polarization, directionality, and UV sensing

Abstract

Digital camera sensors utilize color filters on photodiodes to achieve color selectivity. As color filters and photosensitive silicon layers are separate elements, these sensors suffer from optical cross-talk, which sets limits to the minimum pixel size. In this paper, we report hybrid silicon-aluminum nanostructures in the extreme limit of zero distance between color filters and sensors. This design could essentially achieve sub micron pixel dimensions and minimize the optical cross-talk originated from tilt illuminations. The designed hybrid silicon-aluminum nanostructure has dual functionalities. Crucially, it supports a hybrid Mie-plasmon resonance of magnetic dipole to achieve the color-selective light absorption, generating electron hole pairs. Simultaneously, the silicon-aluminum interface forms a Schottky barrier for charge separation and photodetection. This design could potentially replace the traditional dye based filters for camera sensors at ultra-high pixel densities with advanced functionalities in sensing polarization and directionality, as well as UV selectivity via interband plasmons of silicon.