Abstract

In this paper we demonstrate a new electron spectroscopy technique based on resonant tunneling. The key difference compared to conventional hot electron spectroscopy¹ is the use of a resonant tunneling double barrier in the collector of the structure (Fig. 1). The advantage of this new feature is that it allows one to obtain information on the electron momentum distribution n(p_⊥) (or energy distribution n(E_⊥)) perpendicular to the layers directly from the measured resonant tunneling collector current, without requiring the use of derivative techniques. Figure 1 illustrates the band diagrams of two structures for resonant tunneling electron spectroscopy. The first one (Fig. 1a), realized by us in the present experiment, consists of a reverse biased pn heterojunction and can be used to investigate hot minority carrier transport. Incident light is strongly absorbed in the wide-gap p⁺ layer. Photo-generated minority carrier electrons diffuse to an adjacent low-gap layer. Upon entering this region electrons are ballistically accelerated by the abrupt potential step and gain a kinetic energy ≅ ΔE_c. Collisions in the low gap layer tend to randomize the injected, nearly mono-energetic distribution, making it "hot".

© 1987 Optical Society of America