德国哥廷根大学大学Bnermann, Oliver团队揭示了氢原子与半导体的碰撞能有效地将电子推进导带。相关研究成果发表在2022年11月21日出版的《自然—化学》。

Born–Oppenheimer近似是现代计算化学的基石，人们对理解它在什么条件下仍然有效有着广泛的兴趣。氢原子从绝缘体、半金属和金属表面散射有助于提供此类信息。这个近似值对于绝缘体和金属来说是足够的，但并不严重。

该文中，研究人员提出了氢原子从半导体表面的散射：Ge（111）c（2×8）。实验表明，双峰能量损失分布揭示了两个通道。Born–Oppenheimer近似内的分子动力学轨迹定量地再现了一个通道。第二个通道传输更多的能量，并且在模拟中不存在。它随着氢原子入射能量的增加而增长，并表现出与Ge表面带隙相等的初始能量损失。从而得到结论，在半导体表面的氢原子碰撞能够高效地促进电子从价带到导带。目前的理解无法解释这些观察结果。

附：英文原文

Title: Hydrogen atom collisions with a semiconductor efficiently promote electrons to the conduction band

Author: Krger, Kerstin, Wang, Yingqi, Tdter, Sophia, Debbeler, Felix, Matveenko, Anna, Hertl, Nils, Zhou, Xueyao, Jiang, Bin, Guo, Hua, Wodtke, Alec M., Bnermann, Oliver

Issue&Volume: 2022-11-21

Abstract: The Born–Oppenheimer approximation is the keystone of modern computational chemistry and there is wide interest in understanding under what conditions it remains valid. Hydrogen atom scattering from insulator, semi-metal and metal surfaces has helped provide such information. The approximation is adequate for insulators and for metals it fails, but not severely. Here we present hydrogen atom scattering from a semiconductor surface: Ge(111)c(2 × 8). Experiments show bimodal energy-loss distributions revealing two channels. Molecular dynamics trajectories within the Born–Oppenheimer approximation reproduce one channel quantitatively. The second channel transfers much more energy and is absent in simulations. It grows with hydrogen atom incidence energy and exhibits an energy-loss onset equal to the Ge surface bandgap. This leads us to conclude that hydrogen atom collisions at the surface of a semiconductor are capable of promoting electrons from the valence to the conduction band with high efficiency. Our current understanding fails to explain these observations.

DOI: 10.1038/s41557-022-01085-x