Observation of photo-excited carrier dynamics in semiconductors with time, space, and energy resolutions

Abstract

Semiconductor devices, which have become indispensable in our daily lives, operate based on the movement of charge carriers (electrons and holes) in real and energy spaces. We developed a photoelectron emission microscope (PEEM) with femtosecond laser pulses to evaluate semiconductor materials and devices. In addition to spatial resolution using a PEEM and temporal resolution using laser pulses, the energy resolution is accompanied by continuously varying the photon energy of the laser pulses in the ultraviolet region. As a result, the dynamics of conducting electrons are imaged with a high signal-to-noise ratio. In this paper, we describe the details of the system and present two results on advanced materials.