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L11.13.1

An In-Situ TEM-Cathodoluminescence Study of Electron Beam Degradation of Luminescence from GaN and In0.1Ga0.9N Quantum Wells Nicholas M. Boyall1, Ken Durose1, and Ian M. Watson2 1 Department of Physics, University of Durham, South Road, Durham, DH1 3LE, UK. 2 Institute of Photonics, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, G4 ONW, UK. ABSTRACT The effect of electron beam irradiation on the cathodoluminescence (CL) emission from In0.1Ga0.9N/GaN single quantum wells (QW) has been investigated by in-situ measurement of CL in a transmission electron microscope. Analysis of CL quenching over 600s showed that the QW luminescence decayed more quickly than the barrier emission. Both the In0.1Ga0.9N and GaN CL decay curves could be fitted to a simple recombination based model suggesting the decay was due to the introduction of non-radiative centres. INTRODUCTION Development of GaN electronic devices for high-power, high-frequency transistors (HFETs) and for use in high radiation environments has led to an interest in the degradation behaviour of GaN under electron irradiation [1, 2]. The transmission electron microscope (TEM) provides an ideal vehicle for such studies. Measurement of cathodoluminescence (CL) [3] is routinely done in scanning electron microscopes, and CL in a TEM has been reported by a number of authors [4-7]. More recently TEM-CL has been used in the investigation of InxGa(1-x)N quantum well (QW) structures [8-11]. With this in mind it is of interest to investigate any effects that high energy electron irradiation in a TEM has on the CL emission from these structures. In this work in-situ monitoring of the CL emission from InxGa(1-x)N/GaN QWs has been performed in a TEM. EXPERIMENTAL InxGa(1-x)N/GaN single and double quantum wells were grown by MOVPE on sapphire (0001) substrates. Growth was initiated using a thin low-temperature nucleation layer, which was followed by a one micron thick undoped GaN buffer layer grown at 1140ºC. The quantum well structures were grown at 832ºC. The InGaN quantum wells were nominally 2.5nm thick with a 15nm thick GaN cap. High resolution X-ray diffraction studies and grazing incidence Rutherford back-scattering analysis indicated the indium content of the wells to be x = 0.1 ± 0.015 [12]. Cross section electron transparent specimens (

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