Doping porous silicon with erbium: pores filling as a method to limit the Er-clustering effects and increasing its light emission

Guido Mula (1) , Tony Printemps (2, 3) , Christophe Licitra (2, 3) , Elisa Sogne (4) , Francesco d'Acapito (5) , Narciso Gambacorti (2, 3) , Nicola Sestu (1) , Michele Saba (1) , Elisa Pinna (1) , Daniele Chiriu (1) , Pier Carlo Ricci (1) , Alberto Casu (4) , Francesco Quochi (1) , Andrea Mura (1) , Giovanni Bongiovanni (1) , Andrea Falqui (4)

1 UniCa - Università degli Studi di Cagliari = University of Cagliari
2 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
3 UGA [2016-2019] - Université Grenoble Alpes [2016-2019]
4 King Abdullah Univ Sci & Technol, Biol & Environm Sci & Engn BESE Div, Nabla Lab, Thuwal 239556900, Saudi Arabia
5 ESRF - European Synchrotron Radiation Facility

Er clustering plays a major role in hindering sufficient optical gain in Er-doped Si materials. For porous Si, the long-standing failure to govern the clustering has been attributed to insufficient knowledge of the several, concomitant and complex processes occurring during the electrochemical Er-doping. We propose here an alternative road to solve the issue: instead of looking for an equilibrium between Er content and light emission using 1-2% Er, we propose to significantly increase the electrochemical doping level to reach the filling the porous silicon pores with luminescent Er-rich material. To better understand the intricate and superposing phenomena of this process, we exploit an original approach based on needle electron tomography, EXAFS and photoluminescence. Needle electron tomography surprisingly shows a heterogeneous distribution of Er content in the silicon thin pores that until now couldn't be revealed by the sole use of scanning electron microscopy compositional mapping. Besides, while showing that pore filling leads to enhanced photoluminescence emission, we demonstrate that the latter is originated from both erbium oxide and silicate. These results give a much deeper understanding of the photoluminescence origin down to nanoscale and could lead to novel approaches focused on noteworthy enhancement of Er-related photoluminescence in porous silicon

Domaines: Physique [physics]

Guido Mula, Tony Printemps, Christophe Licitra, Elisa Sogne, Francesco d'Acapito, et al.. Doping porous silicon with erbium: pores filling as a method to limit the Er-clustering effects and increasing its light emission. Scientific Reports, 2017, 7, 12 p. ⟨10.1038/s41598-017-06567-4⟩. ⟨hal-01691821⟩