Carrier dynamics and photodetection in charge injection transistors

Abstract

We study picosecond carrier transport dynamics induced by 200 fs 1.55 m optical pulses in charge injection transistor structures. We propose and demonstrate a new optoelectronic method for exploring the interactions of hot majority carriers and cold minority carriers, as well as the optical control of real space transfer in these devices. The minority holes photogenerated in the channel produce substantial cooling of the hot-electron majority carriers and lead to the reduction of the real space transfer. The new method also provides a direct measure of the minority carrier lifetime in the transistor channel. These effects are demonstrated in InGaAs-channel devices with both InAlAs and InP barriers. The similarities in the device characteristics are explained in terms of the interaction of photogenerated minority holes with majority electrons in the channel leading to a photoconductor-like drain current and to a reduction in the real space transfer collector current. The differences are attributed to the different conduction and valence band energy offsets between the wide band gap barrier and the low band gap collector and channel layers. Furthermore, the InAlAs-barrier device shows a capability of serving as a practical photodetector with the measured, system-limited recovery speed of ϳ5 ps.

Dynamics of Hot Electrons in ZnSe-ZnTe Double Barrier Heterostructures

“…The DBRT structures are also used as a source of the hot electrons injected to the rest of the device and can be implemented into electronic devices such as resonant-tunneling hot electron transistors (RHETs) [1,2]. The growing number of practical applications increases interest in investigation of the electron dynamics in such devices [3,4].…”