Photoconductivity and photoluminescence under bias in GaInNAs/GaAs MQW p-i-n structures

Hagir M Khalil,Ben Royall,Naci Balkan,Simone Mazzucato

doi:10.1186/1556-276x-7-539

Abstract

The low temperature photoluminescence under bias (PLb) and the photoconductivity (PC) of a p-i-n GaInNAs/GaAs multiple quantum well sample have been investigated. Under optical excitation with photons of energy greater than the GaAs bandgap, PC and PLb results show a number of step-like increases when the sample is reverse biased. The nature of these steps, which depends upon the temperature, exciting wavelength and intensity and the number of quantum wells (QWs) in the device, is explained in terms of thermionic emission and negative charge accumulation due to the low confinement of holes in GaInNAs QWs. At high temperature, thermal escape from the wells becomes much more dominant and the steps smear out.

Highlights

Dilute nitride research has sparked considerable interest from fundamental physics to industrial applications, and nowadays, several devices based on GaInNAs/GaAs heterostructures are commercially available [1,2,3,4,5,6,7]
The distinct tail extending from the low energy side of the quantum wells (QWs) PL emission indicates strong carrier localisation where electrons become trapped in states below the conduction band and recombine radiatively [16,17]
Photocurrent and integrated photoluminescence measurements on a GaInNAs/GaAs multi-quantum well based p-i-n diode are performed at T = 100 K as a function of applied bias

Summary

Introduction

Dilute nitride research has sparked considerable interest from fundamental physics to industrial applications, and nowadays, several devices based on GaInNAs/GaAs heterostructures are commercially available [1,2,3,4,5,6,7]. The interest on this material started from the discovery that adding small amounts of nitrogen to GaAs and GaInAs resulted in a relatively large redshift in bandgap [8], leading to the realisation of 1.3- and 1.55 μm wavelength devices [9] with strong electron confinement with the use of the well-established GaAs technology. These results give a more complete understanding of the underlying mechanisms such as thermal escape, trapping, recombination and charge accumulation

Methods

Results

Conclusion