Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Poster Wednesday: Organic Molecules at Surfaces 2

O 55.7: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P4

Photoemission and Raman Spectroscopic Studies of n-GaAs(100) Surface Passivation with Thioglycolic Acid — •Alexander Ehm, Oleksandr Selyshchev, and Dietrich R. T. Zahn — Semiconductor Physics, TU Chemnitz, Chemnitz D-09107, Germany

Gallium arsenide is one of the most investigated inorganic semiconductors and used in a vast variety of applications and prospective for new high-performance devices. A challenge in constructing such devices is a surface of native oxides causing a high surface density of states, which leads to the mid-gap pinning of the surface Fermi level, band bending, and the formation of a surface depletion layer. Sulphur passivation yields a significant reduction of the depletion layer and related effects but requires several treatment steps [1].

We report a new simple approach utilizing thioglycolic acid (TGA) to provide a one-step effective removal of surface oxides and protection from reoxidation compared to etching with inorganic acids. This effect is confirmed by X-ray photoemission spectroscopy and the reduction of the depletion layer is confirmed by Raman spectroscopy results. n-GaAs(100)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) solar cells show improved performance for such passivated n-GaAs(100) surfaces.

[1] V. N. Bessolov, M.V. Lebedev, D. R. T. Zahn: J. Appl. Phys. 82 (5) (1997)