Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 60: III-V Semiconductors (no Nitrides)

HL 60.8: Vortrag

Mittwoch, 9. März 2016, 17:00–17:15, H13

Suppression of rotational twin domains in GaP epilayers on Si(111) for improved III-V nanowire growth — •Christian Koppka, Agnieszka Paszuk, Matthias Steidl, Peter Kleinschmidt, and Thomas Hannappel — TU Ilmenau, Institute of Physics, D-98693 Ilmenau, Germany

The growth of a high-quality GaP epilayer on Si(111) could lead to promising hetero-substrates for optoelectronic devices such as high efficiency NW-based multi-junction solar cells, LEDs and fast photo-detectors [1]. Low defect densities in the buffer layer are required for further III/V integration and superior optoelectronic properties of the GaP itself. However, epitaxially grown III-V layers on (111) oriented substrates tend to form rotational twin domains (RTDs), which results in multicrystalline layers with poor surface quality [1-2]. In order to suppress the formation of RTDs the impact of the substrate misorientation as well as nucleation conditions during MOVPE growth were investigated. Combining HRXRD, SEM and AFM, we reveal a significant influence of nucleation temperature and substrate offcut direction on the formation of RTDs. The epilayer quality is drastically increased by a low temperature nucleation step. Using Si(111) substrates with 3° misorientation towards <-1-12> as well as improved nucleation conditions the twinned GaP domains are suppressed below 4%. We demonstrate that these quasi-substrates are highly suitable for vertical GaP nanowire growth. [1]I. Miccoli et al., Cryst. Res.Technol. 46, 795 (2011) [2]H. A. Fonseka et al., Nanotechnol. 24, 465602 (2013)