2D-3D integration of hBN and a high-κ dielectric for ultrafast graphene-based electro-absorption modulators

Abstract

Electro-absorption (EA) waveguide-coupled modulators are essential building blocks for on-chip optical communications. Compared to state-of-the-art silicon (Si) devices, graphene based EA modulators promise smaller footprints, larger temperature stability, cost-effective integration and high speeds. However, combining high speed and large modulation efficiencies in a single graphene-based device has remained elusive so far. In this work, we overcome this fundamental trade-off by demonstrating the first 2D-3D dielectric integration in a high-quality encapsulated graphene device. We integrated hafnium oxide (HfO2) and two-dimensional hexagonal boron nitride (hBN) within the insulating section of a double-layer (DL) graphene EA modulator. This novel combination of materials allows for a high-quality modulator device with record high performances: a ∼39GHz bandwidth (BW) with a three-fold increase in modulation efficiency compared to previously reported high speed modulators. This first demonstration of 2D-3D integration paves the way to a plethora of electronic and opto-electronic devices with enhanced performance and stability, while expanding the freedom for new device designs.

Balancing the Photo‐Induced Carrier Transport Behavior at Two Semiconductor Interfaces for Dual‐Polarity Photodetection

“…[ 2,3,11,12 ] For instance, monolithic integration of dissimilar single‐crystalline low dimensional materials, a hybrid 2D/3D novel device architecture, or semiconductor nanowire system with large surface‐to‐volume ratio feature are particularly attractive for emerging multi‐functional electronic and photonic devices. [ 13–16 ] Hence, it is critical to deeply understand the SSIE first and then rationally utilize them to manipulate the semiconductor surface or hetero‐interface from which we can renovate or tune the device functionality and promote new applications that are barely attainable in regular device architecture.…”