# ZnO Doping-Induced Performance Boost in Co2TiO4/n-Si Schottky Self-Powered Photodetectors

## TL;DR

Adding ZnO to Co2TiO4 improves the performance of self-powered photodetectors by boosting light absorption and sensitivity.

## Contribution

ZnO doping in Co2TiO4/n-Si Schottky photodetectors is shown to significantly enhance optoelectronic performance.

## Key findings

- ZnO doping increased responsivity from 0.35 to 17.39 mA/W at 351 nm and from 1.75 to 23.76 mA/W at 1000 nm.
- Specific detectivity surpassed 10^10 Jones across much of the spectrum, with noise equivalent power decreasing significantly.
- External quantum efficiency improved from 0.13 to 6.43% at 351 nm under 20 mW/cm² illumination.

## Abstract

In this study, we employed Co2TiO4 and synthesized
ZnO-doped Co2TiO4 nanocomposites, which were
utilized as interlayers in silicon-based Schottky photodetectors for
optoelectronic characterization. Structural analyses using XRD, SEM,
and EDX confirmed successful fabrication. The photodetectors were
evaluated across a broad spectral range (351–1600 nm) and under
varying light intensities. The incorporation of ZnO nanoparticles
significantly enhanced the performance of the Co2TiO4-ZnO/n-Si device compared to its undoped counterpart. Notably,
the responsivity (R) improved from 0.35 to 17.39
mA/W at 351 nm and from 1.75 to 23.76 mA/W at 1000 nm. Correspondingly,
the specific detectivity increased by nearly an order of magnitude,
surpassing 1010 Jones across much of the spectrum. The
noise equivalent power (NEP) decreased drastically from 2.16 ×
10–10 to 1.03 × 10–11 W·Hz–1/2 at 351 nm and from 4.33 × 10–11 to 7.53 × 10–12 W. Hz–1/2 at 1000 nm, indicating enhanced sensitivity. The external quantum
efficiency (EQE) also improved from 0.13 to 6.43% at 351 nm, with
sustained enhancement in the UV–vis-NIR regions. Under 20 mW/cm2 illumination, the Co2TiO4-ZnO/n-Si
device exhibited a responsivity of 85.99 mA/W compared to 10.23 mA/W
for the Co2TiO4/n-Si device, and a detectivity
of 4.26 × 1010 Jones, significantly higher than 1.03
× 1010 Jones for the undoped counterpart. These results
demonstrate that ZnO doping significantly improves light absorption,
carrier transport, and signal-to-noise ratio, making the Co2TiO4-ZnO/n-Si photodetector a promising candidate for
high-performance, broadband, self-powered photodetection applications.