Designing near-infrared electro-optical devices from the SrTiO₃/LaAlO₃ materials system

Abstract

While the SrTiO3/LaAlO3 materials system has garnered intense research interest over the past decade owing to the discovery of a two-dimensional electron gas at the interface of these two band insulators, recent reports have focused on its optical properties. The silicon-compatibility of the SrTiO3/LaAlO3 system, together with its large conduction band offset and the ability to confine charge carriers in SrTiO3 quantum wells, makes it a potential candidate for use in a wide range of integrated photonics applications. Here, we present numerical simulations of the electrical, optical, and electro-optical performance of silicon-integrated SrTiO3/LaAlO3 electro-optical devices utilizing the quantum-confined Stark effect to electro-optically tune intersubband absorptions occurring at near-infrared optical wavelengths. We discuss optimal design parameters for the fabrication of experimentally realizable devices and attempt to minimize the energy consumption of a SrTiO3/LaAlO3 electro-optic modulator while maximizing performance. We predict modulation energies on the order of tens of pJ/bit for the proposed device. Our results indicate the feasibility of producing SrTiO3/LaAlO3-based integrated electro-optical devices using existing thin film growth and semiconductor processing techniques.