Effect of modulation-doping on luminescence properties of plasma assisted MBE-grown GaN/AlGaN quantum well

¹ Dept. of Functional Materials Science, Saitama University, Saitama-shi, Saitama 338-8570, Japan
² Lab. für Informationstechnologie, Universität Hannover, Schneiderberg, Hannover 30167, Germany
³ Research Center for Advanced Science and Techn., Univ. of Tokyo, Meguro-ku, Tokyo 153-8904, Japan

Corresponding author: kamata@fms.saitama-u.ac.jp

Received: 4 July 2003
Accepted: 28 January 2004
Published online: 15 July 2004

Abstract

In order to improve the crystal quality of GaN-based light emitting devices, photoluminescence (PL) characterization of below-gap states in plasma assisted MBE-grown GaN/AlGaN quantum well (QW) structures has been done by utilizing a below-gap excitation (BGE) light in addition to an above-gap excitation light. The decrease of the band-edge PL intensity due to the addition of the BGE of 1.17 eV indicates the presence of an energy-matched below-gap state in the two-wavelength excited PL. In continuation to our previous efficiency improvement by applying modulation-doping to GaAs/AlGaAs QW's, we focused on several undoped and Si-doped GaN/AlGaN QW's. Experimental results showed that Si modulation-doping reduces the density of below-gap states in the QW region, hence it is promising for increasing internal quantum efficiency of GaN-based QW's.