Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 83: Heterostructures and Interfaces

O 83.1: Vortrag

Donnerstag, 10. März 2016, 09:30–09:45, H17

Silicon p-n junctions prepared by group-V in-diffusion in CVD ambient — •Agnieszka Paszuk, Oliver Supplie, Marek Duda, Anja Dobrich, Peter Kleinschmidt, Sebastian Brückner, and Thomas Hannappel — Technische Universität Ilmenau, Institut für Physik, Fachgebiet Photovoltaik, Gustav-Kirchhoff-Str. 5, 98693 Ilmenau, Germany

Integration of III-V materials with Si substrates is promising for high-efficiency tandem solar cells. Preparation of Si bottom cell in MOCVD environment requires control over the doping. Phosphorus (P) in-diffusion into crystalline Si is a complex process, but has been shown suitable to form a working emitter [1,2]. Arsenic (As) in-diffusion on the other hand is interesting since Si surfaces terminated with As enable the prepareation of B-type GaP/Si(111)[3] and As-based planar graded buffer layers. Here, we focus on As and P in-diffusion and its impact on the Si surface (controlled by in-situ reflection anisotropy spectroscopy). Diffusion of As and P into Si is carried out by annealing the substrates under TBAs or TBP. We investigated the diffusion in dependence on duration and temperature of the annealing step, precursor source, reactor pressure and post diffusion annealing. Annealing the Si surface in presence of the precursors results in surface roughening and a disordered surface. Subsequent annealing without precursor supply leads to a re-ordered dimerized surface. [1] E. García-Tabarés et al., 8th International Conference on Concentrating Photovoltaic Systems (2012). [2] R. Varache et al., Energy Procedia 77, 493 (2015). [3] A. Paszuk et al., Appl. Phys. Lett. 106, 231601 (2015).