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Influence of Er depth profiles on luminescence properties of Er-doped GaN Shin-ichiro Uekusa and Tomoaki Hirano Department of Electrical and Electronic Engineering, Meiji University, 1-1-1 Higashi-mita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan ABSTRACT Erbium (Er) ions were implanted into gallium nitride (GaN) and the temperature-dependent photoluminescence (PL) and PL lifetime were characterized. Thermal quenching of the Er3+ luminescence was restrained by using GaN as a host material and PL was observed from Er3+ at room temperature. We prepared a flat depth profile of the density distribution of Er by ion-implanted into GaN and monitored the thermal quenching process due to the residual defects after implantation and annealing. We also monitored the auger effect that is believed to be the main cause of the thermal quenching process and concluded that, in the temperature range 15 K to 100 K, the thermal quenching process is dominated by nonradiative recombination from the first excited state (4I13/2) to the ground state (4I15/2) of Er3+. INTRODUCTION An Erbium (Er)-doped semiconductor is a potentially useful material for use in light-emitting devices in optical communication systems, since the intra-4f-shell transitions of Er ions cause sharp and temperature-stable luminescence in various host materials [1,2] at 1.54 µm, which corresponds to the minimum absorption of silica-based optical fibers. Photoluminescence (PL) from Er3+ in Er-doped narrow-band-gap semiconductors (e.g., silicon (Si)) has been reported [3-7], but the PL is weak and difficult to observe at room temperature. One of the reasons for the difficulties in obtaining the Er3+ PL at room temperature is the low probability of Er excitation via recombination of free carriers, as has been theoretically explained by Needles et al. [8]. However, an increase of Er3+ luminescence could be realized by using a wide-band-gap material as a host material. The influence of the introduction of light elements on Er3+ luminescence in Si:Er and GaP:Er was previously studied by us using standard PL and PL excitation (PLE) techniques [1,2]. We proposed that light elements form complexes with the Er atoms, causing an efficient excitation of Er3+ via a recombination of electron-hole (e-h) pairs, where one of the carriers is localized at the Er complex-related deep levels in the forbidden-gap [1]. Gallium nitride (GaN) is a very useful host material because it equips a wide band gap and improves the luminescence properties of the Er3+ ions [9-12]. In this work, we implanted Er into an undoped and a Si-doped epitaxial n-GaN layer (GaN:Er) grown on a sapphire substrate by the MOCVD method and studied the luminescence properties of Er3+ ions with respect to annealing temperature, Er dose and temperature dependences of activation energy values. G6.15.1

EXPERIMENTAL DETAILS The wafer used in this work was an undoped (n=1-5x1016 cm-3) and a Si doped (n=1-5x1018 cm-3) epitaxial GaN layer (obtained from Eptronics) grown on a sapphire substrate. Er implantation was performed