Ultrafast unidirectional on-chip heat transfer

Abstract Effective and rapid heat transfer is critical to improving electronic components' performance and operational stability, particularly for miniaturized devices with high heat dissipation demands. However, current thermal manipulation approaches, including the recent advancement in thermal metamaterials, cannot realize fast and unidirectional control of the heat flow path. In addition, any defects in thermal conductive materials cause a significant decrease in thermal conductivity, severely degrading heat transfer performance. Here, we demonstrate a new approach to achieve ultrafast unidirectional on-chip heat transfer. Using silicon-based valley photonic crystals (VPCs), we have realized robust unidirectional heat transfer through thermal radiation in the infrared wavelength region. This approach can facilitate heat transfer through arbitrarily designed heat flow paths with near-unity heat transmission efficiency independent of temperature. Furthermore, the design exhibits defect immune heat transfer capability due to the unique properties of VPC structures. It opens new possibilities in heat transfer without the inherent limitations of conventional conductive heat transfer mechanism, which inevitably heats up the entire devices, causing severe performance degradation and energy waste. The design is fully CMOS compatible, thus, will find broad applications, particularly in heat dissipation for integrated optoelectronic devices.