MRS Communications

Research Letters

Carrier-induced nonlinearities in InGaN/GaN quantum wells with V-pits

Meg Mahata1, Antonio Llopisa1, Richard D. Schallera2, Ian Watsona3, Sergio Perieraa4 and Arup Neogia5 c1

a1 Department of Physics, University of North Texas, Denton, Texas 76203

a2 Argonne National Laboratory, Center for Nanoscale Materials, Argonne, Illinois 60439

a3 SUPA, Institute of Photonics, University of Strathclyde, Glasgow, UK

a4 CICECO, Universidade de Aveiro, 3810-193 Aveiro, Portugal

a5 Department of Physics, University of North Texas, Denton, Texas 76203

Abstract

Ultrafast differential transmission spectroscopy was employed to study the carrier dynamics in InGaN/GaN multiple quantum wells with high inverted hexagonal pits density due to threading dislocation. By monitoring the temporal evolution of the excitonic absorption spectrum, a reduction of the quantum-confinement Stark shift was observed due to the photo-induced in-well field screening at low carrier densities and excitonic absorption quenching at high carrier densities. By comparing the differential absorption spectra at various injected carrier densities, the in-well field screening effect was distinguished from excitonic bleaching.

(Received March 06 2012)

(Accepted May 22 2012)

Correspondence:

c1 Address all correspondence to A. Neogi at arup@unt.edu

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