Local Structure and Er3+ Emission from Pseudo-Amorphous GaN:Er Thin Films

Abstract

AbstractWe report on strong Er3+ luminescence in the visible and infra-red regions at room temperature in amorphous GaN:Er thin films prepared by DC magnetron co-sputtering. The intensity of the Er3+ luminescence at 1.535 μm corresponding to 4I13/2 → 4I15/2 transitions is greatly enhanced after annealing at 750°C. In this material GaN crystallites have formed and embedded in the continuous amorphous matrix. The crystallites are 4 to 7 nm in diameter as analyzed by high resolution transmission electron microscopy. The absorption edge, extending three orders of magnitude in absorption coefficient in the spectral range from 0.5 to 3.5 eV, is superimposed on resonant absorption bands of Er3+ ions.The total photoluminescence spectrum consists of welldefined Er3+ luminescence peaks imposed on a broad band edge luminescence from the amorphous GaN host matrix.