The photoelectric effect has a sister process relevant in optoelectronics called internal photoemission^1,2,3. Here an electron is photoemitted from a metal into a semiconductor^4,5. While the photoelectric effect takes place within less than 100 attoseconds (1 as = 10⁻¹⁸ seconds)^6,7, the attosecond timescale has so far not been measured for internal photoemission. Based on the new method CHArge transfer time MEasurement via Laser pulse duration-dependent saturation fluEnce determinatiON—CHAMELEON—we show that the atomically thin semimetal graphene coupled to bulk silicon carbide, forming a Schottky junction, allows charge transfer times as fast as (300 ± 200) as. These results are supported by a simple quantum mechanical model simulation. With the obtained cut-off bandwidth of 3.3 PHz (1 PHz = 10¹⁵ Hz) for the charge transfer rate, this semimetal/semiconductor interface represents a functional solid-state interface offering the speed and design space required for future light-wave signal processing.

光电效应具有与光电相关的姐妹过程，称为内部光发射^1,2,3。在这里，电子从金属光发射到半导体^4,5中。光电效应发生在不到100阿秒内（1等于10 ^-18秒）^6,7，到目前为止，尚未测量内部光发射的秒级时标。基于新方法，通过与激光脉冲持续时间有关的饱和通量测定（CHAMELEON）来测量电荷转移时间，我们证明，原子薄的半金属石墨烯与块状碳化硅偶联形成了肖特基结，电荷转移时间快于（300± 200）。这些结果得到简单的量子力学模型仿真的支持。由于获得 的电荷传输速率的截止带宽为3.3 PHz（1 PHz = 10 ¹⁵ Hz），因此这种半金属/半导体接口代表了一种功能性的固态接口，可提供未来光波信号处理所需的速度和设计空间。