Terahertz sensing by beryllium and silicon delta-doped GaAs/AlAs quantum wells

TL;DR

This paper demonstrates terahertz sensing using beryllium and silicon delta-doped GaAs/AlAs quantum wells, achieving high sensitivity at cryogenic temperatures within specific THz frequency ranges.

Contribution

It introduces a novel approach for THz detection employing delta-doped quantum wells with detailed sensitivity measurements and electric field estimations.

Findings

Sensitivity up to 0.3 V/W in silicon-doped MQWs

Sensitivity up to 1 V/W in beryllium-doped MQWs

Built-in electric fields estimated between 18 kV/cm and 49 kV/cm

Abstract

Selective sensing of terahertz (THz) radiation by beryllium and silicon delta-doped GaAs/AlAs multiple quantum wells (MQWs) is demonstrated. A sensitivity up to 0.3 V/W within 0.5{4.2 THz in silicon- and up to 1 V/W within 4.2-7.3 THz range in beryllium-doped MQWs at liquid helium temperatures is shown. The built-in electric fields as estimated from the observed Franz-Keldysh oscillations in photoreflectance spectra were found to be located close to the cap and buffer layers of MQWs and vary from 18 kV/cm up to 49 kV/cm depending on the structure design.