Intense NIR emission in YVO4:Yb3+ thin films by atomic layer deposition

Abstract

We demonstrate controlled deposition by atomic layer deposition of YVO4:Yb3+ thin films exhibiting an intense NIR emission under UV excitation after post-deposition annealing at 1000 °C. The samples are deposited using the precursor combinations Yb(thd)3, Y(thd)3, and VO(thd)2 with O3 (thd = 2,2,6,6-tetramethyl-3,5-heptanedione) at deposition temperatures between 260 and 300 °C. The NIR emission is expected to be due to a quantum splitting process in which one UV photon is converted to two NIR photons. In the present contribution we assess the efficiency of the UV to NIR conversion in the produced films and determine the optimal pulse parameters with respect to NIR emission intensity. We also demonstrate the synthesis of a crystalline YVO4:YbVO4 layered material by ALD to verify the possibility of creating artificial core–shell type structures. The structure, thickness, and composition of the deposited films have been studied by X-ray diffraction, ellipsometry, and X-ray fluorescence, respectively.