Deep-ultraviolet transparent conducting SrSnO3 via heterostructure design

TL;DR

This study demonstrates a heterostructure design enabling SrSnO3 to achieve both high transparency and high conductivity for deep-ultraviolet optoelectronic applications, with mobility up to 140 cm2V-1s-1 and 85% transparency at 300 nm.

Contribution

The paper introduces a heterostructure approach to simultaneously enhance transparency and conductivity in SrSnO3, a significant advancement over previous single-layer materials.

Findings

Achieved 85% transparency at 300 nm wavelength.

Modulated carrier density from 10^18 to 10^20 cm^-3 with gating.

Room temperature mobility ranged from 40 to 140 cm^2V^-1s^-1.

Abstract

Exploration and advancements in ultra-wide bandgap (UWBG) semiconductors are pivotal for next-generation high-power electronics and deep-ultraviolet (DUV) optoelectronics. A critical challenge lies in finding a semiconductor that is highly transparent to DUV wavelengths yet conductive with high mobility at room temperature. Here, we achieved both high transparency and high conductivity by employing a thin heterostructure design. The heterostructure facilitated high conductivity by screening phonons using free carriers, while the atomically thin films ensured high transparency. We utilized a heterostructure comprising SrSnO3/La:SrSnO3/GdScO3 (110) and applied electrostatic gating to effectively separate electrons from their dopant atoms. This led to a modulation of carrier density from 1018 cm-3 to 1020 cm-3, with room temperature mobilities ranging from 40 to 140 cm2V-1s-1. The phonon-limited mobility, calculated from first principles, closely matched experimental results, suggesting that room-temperature mobility could be further increased with higher electron density. Additionally, the sample exhibited 85% optical transparency at a 300 nm wavelength. These findings highlight the potential of heterostructure design for transparent UWBG semiconductor applications, especially in deep-ultraviolet regime.