Circular photogalvanic effect in HgTe/CdHgTe quantum well structures

TL;DR

This paper reports the observation of circular and linear photogalvanic effects in HgTe/CdHgTe quantum wells, demonstrating how mid-infrared and terahertz radiation induce polarization-dependent dc currents explained by phenomenological theory.

Contribution

First experimental observation of circular and linear photogalvanic effects in HgTe/CdHgTe quantum wells with analysis of their dependence on radiation parameters.

Findings

Photocurrent depends on radiation polarization and substrate orientation.

Photocurrent varies with wavelength and temperature.

Phenomenological theory explains the observed effects.

Abstract

We describe the observation of the circular and linear photogalvanic effects in HgTe/CdHgTe quantum wells. The interband absorption of mid-infrared radiation as well as the intrasubband absorption of terahertz (THz) radiation in the QWs structures is shown to cause a dc electric current due to these effects. The photocurrent magnitude and direction varies with the radiation polarization state and crystallographic orientation of the substrate in a simple way that can be understood from a phenomenological theory. The observed dependences of the photocurrent on the radiation wavelength and temperature are discussed.