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HL: Fachverband Halbleiterphysik

HL 35: Poster I

HL 35.23: Poster

Tuesday, March 8, 2016, 15:00–19:00, Poster A

Deep electronic levels in crystalline silicon after irradiation with femtosecond laser pulses in SF₆-atmosphere — •Arne Ahrens¹, Philipp Saring¹, Anna Lena Baumann², Stefan Kontermann^2,3, and Michael Seibt¹ — ¹IV. Physikalisches Institut, Georg-August Universität Göttingen, Germany — ²Fraunhofer Heinrich Hertz Institut, Goslar, Germany — ³present address: Hochschule RheinMain, Rüsselsheim, Germany

Femtosecond laser pulse irradiation in sulfur hexafluoride (SF₆) atmosphere leads to sulfur incorporation into the silicon beyond the solubility limit (hyperdoping) and structuring of the surface. Enhanced optical absorption in the sub-bandgap range due to introduced deep defect levels is known for such materials. This makes such a material a promising candidate for intermediate band solar cell applications, especially if impurity bands form due to a Mott transition. Considering a p-type silicon substrate, sulfur hyperdoping leads to the formation of a buried pn-junction which has been studied in detail by means of cross-section transmission electron microscopy (TEM) and electron-beam induced current (EBIC) [1] as well as capacitance-voltage (CV) and SIMS measurements [2]. This work presents results of additional cross sectional EBIC and TEM experiments. Furthermore, this work presents the results of an extensive deep-level transient spectroscopy (DLTS) study of deep levels in the vicinity of the buried pn-junction, which points out the existence of two dominant deep levels. [1] P. Saring et al., Appl. Phys. Lett. 103, 061904 (2013). [2] K.-M. Guenther et al., Appl. Phys. Lett. 102, 202104 (2013).