Asymmetrically Doped GaAs/AlGaAs Double-Quantum-Well Structure for Voltage-Tunable Infrared Detection

Abstract

We fabricate, characterize, and analyze tunable mid-infrared photodetectors based on asymmetrically doped coupled quantum well GaAs/ AlGaAs structures. The peak of photoresponse detection varies from 7.5 to 11.1 m when switching bias from À5 to +5 V. The spectral tunability is defined by the interplay of several effects. First, the electron energy levels are shifted due to the Stark effect. Second, the applied electric field causes the charge redistribution in the coupled wells and shift of electron energy levels due to modification of self-consistent potential. Here we show that effect of electric field on tunneling processes (the Poole-Frenkel effect) and the field-induced decrease of thermo-emission barrier (the Fowler-Nordheim effect) also play a critical role in photoelectron kinetics, strongly enhancing the carrier extraction from quantum wells. The model which takes into account Poole-Frenkel and Fowler-Nordheim effects provides a quantitative description of the data obtained.

Development of voltage-tunable IR photodetector

“…These imagers contain two vertically stacked focal plane arrays operating in separate IR bands and were proven useful for contrast and object recognition improvements [4,5]. More recently, another unique property of intersubband transitions was explored in the QWIPs, namely the ability to effectively control the QW potential by the external bias, and thus tuning the QWIP spectral sensitivity [6][7][8]. This type of detector can find its niche application in the imaging sensors driven by object recognition AI algorithms requiring on-demand spectral tuning to account for changing environmental conditions and thermal characteristics of the object.…”

Oscillation of Electron Mobility in V‐Shaped Double Quantum Well Structure Under Applied Electric Field

“…By varying the structure parameters such as well width, barrier width, and doping concentration, the strength of the coupling can be varied . Attempts have been made to utilize DQW structures for the development of field effect transistors . The application of external electric field F tilts the potential profile of the quantum well.…”

Electron Mobility in AlxGa1−xAs Based Square‐Parabolic Double Quantum Well HEMT Structure − Effect of Asymmetric Doping Profile

“…In recent years, double quantum well structures have become important not only for their use as test materials to study the fundamentals of coupled two dimensional electron gas (2DEG), but also for their application in developing electronic and optical devices. [1][2][3][4][5][6] In a double quantum well, the coupling of subband wave functions of the individual wells through the central barrier splits the energy levels thereby acts as an additional degree of freedom to control the subband states. [3][4] Several attempts have been made to study the electron mobility of the double quantum well by varying the well width, doping concentration, and barrier width.…”

“…The subband energy levels of the individual wells coincide exhibiting resonance and thereby forming the coupled double quantum well structure. [6,25,26] Accordingly the ground state of the individual wells split into a doublet, forming the lowest E 0 and first excited E 1 subband energy levels of the coupled structure. The separation between E 0 and E 1 relates to the coupling between the eigen states of the wells, the strength of which depends on the width and height of the central barrier.…”

“…At N d1 = N d2 , the system becomes symmetric. The subband energy levels of the individual wells coincide exhibiting resonance and thereby forming the coupled double quantum well structure . Accordingly the ground state of the individual wells split into a doublet, forming the lowest E 0 and first excited E 1 subband energy levels of the coupled structure.…”