Direct observation and manipulation of hot electrons at room temperature

Wang, H. and Wang, F. and Xia, H. and Wang, P. and Li, T. and Li, J. and Wang, Z. and Sun, J. and Wu, P. and Ye, J. and Zhuang, Q. and Yang, Z. and Fu, L. and Hu, W. and Chen, X. and Lu, W. (2021) Direct observation and manipulation of hot electrons at room temperature. National Science Review, 8 (9): nwaa295. ISSN 2053-714X

Abstract

In modern electronics and optoelectronics, hot electron behaviors are highly concerned, as they determine the performance limit of a device or system, like the associated thermal or power constraint of chips and the Shockley-Queisser limit for solar cell efficiency. To date, however, the manipulation of hot electrons has been mostly based on conceptual interpretations rather than a direct observation. The problem arises from a fundamental fact that energy-differential electrons are mixed up in real-space, making it hard to distinguish them from each other by standard measurements. Here we demonstrate a distinct approach to artificially (spatially) separate hot electrons from cold ones in semiconductor nanowire transistors, which thus offers a unique opportunity to observe and modulate electron occupied state, energy, mobility and even path. Such a process is accomplished through the scanning-photocurrent-microscopy measurements by activating the intervalley-scattering events and 1D charge-neutrality rule. Findings here may provide a new degree of freedom in manipulating non-equilibrium electrons for both electronic and optoelectronic applications.