Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster I

HL 13.56: Poster

Monday, March 18, 2024, 15:00–18:00, Poster E

Photoemission study and band alignment of GaN passivation layers on GaInP(100) heterointerfaces — •Sahar Shekarabi¹, Mohammad Amin Zare Pour¹, Haoqing Su², Wentao Zhang², Chengxing He², Oleksandr Romanyuk³, Agnieszka Paszuk¹, Shu Hu², and Thomas Hannappel¹ — ¹Grundlagen von Energiematerialien, Institut fur Physik, Technische Universit at Ilmenau, 98693 Ilmenau, Germany — ²Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06520, USA — ³FZU Institute of Physics of the Czech Academy of Sciences, Cukrovarnicka 10, Prague 16200, Czech Republic

GaInP(100) is commonly used as a top photoabsorber in tandem devices and photoelectrochemical (PEC) cells. Since the photo corrosion degrades the cell stability and efficiency, GaN is used as a promising passivation layer. Therefore, studying the band alignment at this heterointerface is crucial for efficient charge transfer and minimizing photovoltage losses. Here, we study the band alignment of the multi-junction heterostructure by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. GaInP(100) layers were grown by metalorganic chemical vapor deposition on top of GaAs(100), with a P-rich surface reconstruction. GaN passivation layers were grown by atomic layer deposition on oxidized GaInP(100) surfaces. On the P-rich n-GaInP(100) we found upward surface BB of 0.44 eV. Oxidation partly passivates surface states, lowering BB to 0.16 eV. Between the GaInP(100) and GaN passivation layer, we found a VBO of 1.9 eV, suggesting efficient electron transport but impeding hole transport.

Keywords: GaInP(100); GaN; band alignment; MOCVD; X-ray photoelectron spectroscopy