Damping of the Franz-Keldysh oscillations in the presence of disorder

TL;DR

This paper theoretically investigates how short-range disorder dampens Franz-Keldysh oscillations in optical absorption, especially at high frequencies, highlighting the role of electron and hole sensitivities near turning points.

Contribution

It provides a theoretical analysis of the damping mechanism of Franz-Keldysh oscillations caused by disorder, emphasizing the dependence on mean-free path and electric field parameters.

Findings

Damping increases at high absorption frequencies.

Disorder effects are amplified near electron and hole turning points.

Damping depends on the relation between mean-free path and turning point distance.

Abstract

Franz-Keldysh oscillations of the optical absorption in the presence of short-range disorder are studied theoretically. The magnitude of the effect depends on the relation between the mean-free path in a zero field and the distance between the turning points in electric field. Damping of the Franz-Keldysh oscillations by the disorder develops at high absorption frequency. Effect of damping is amplified by the fact that, that electron and hole are most sensitive to the disorder near the turning points. This is because, near the turning points, velocities of electron and hole turn to zero.