Electric field gradient induced effects in GaAs/AlGaAs modulation-doped structures and high frequency sensing

TL;DR

This study investigates how electric field gradients in asymmetrically shaped GaAs/AlGaAs structures affect their electrical properties and explores their potential for high-frequency electromagnetic radiation detection.

Contribution

It demonstrates the influence of electric field gradients on current-voltage asymmetry and models this effect with experiments, Monte Carlo simulations, and discusses applications in GHz and THz detection.

Findings

Asymmetrical structures show pronounced I-V asymmetry at low temperatures.

Electric field gradients are caused by structural asymmetry and electron drift nonlocality.

Potential for high-frequency electromagnetic radiation sensing is identified.

Abstract

Electric field gradient effects induced by an asymmetrically in-plane shaped GaAs/AlGaAs modulation-doped structures of various design are investigated within 4-300 K temperature range. It is demonstrated that current-voltage characteristics of such structures at low, 4-80 K, temperatures exhibit well-pronounced asymmetry arising due to a presence of two different gradients of the electric field in a two dimensional electron gas. This phenomenon is caused by both, different accumulation of two-dimensional electrons due to asymmetrical shape of the structure and nonlocality in the electron drift velocity. Experiments are illustrated by a phenomenological model and Monte Carlo simulation. Possible applications of the effect to detect electromagnetic radiation of GHz and THz frequencies are discussed as well.