GaAs (1 1 1) epilayers grown by MBE on Ge (1 1 1): Twin reduction and polarity

D. Pelati (1) , G. Patriarche (1) , O. Mauguin (1) , L. Largeau (1) , L. Travers (1) , F. Brisset (2) , F. Glas (1) , F. Oehler (1)

1 C2N - Centre de Nanosciences et de Nanotechnologies
2 ICMMO - Institut de Chimie Moléculaire et des Matériaux d'Orsay

We perform the growth of GaAs (1 1 1) epilayers on nominal Ge(1 1 1) wafers by molecular beam epitaxy (MBE). The polarity of GaAs is (1 1 1)A and homongeneous over the full area, as measured by transmission electron microscopy and high energy electron diffraction. This orientation conflicts with the common growth model for GaAs on Ge(1 1 1). Twinned domains are the main defects in our GaAs (1 1 1) epilayers. Using cathodoluminescence, we observe that some twin boundaries hold large number of non-radiative recombination centers. During growth, we find that only a narrow domain of As:Ga ratios lead to the growth of smooth and twin-free GaAs (1 1 1)A epilayers. At low As:Ga ratio, the surface is rough; while at high As:Ga ratio the epilayers present large densities of twinned domains.

Keywords: Molecular Beam Epitaxy; GaAs; Ge; twin; defect; (111); heteroepitaxy

Domains: Chemical Sciences; Material chemistry; Chemical Sciences; Inorganic chemistry

D. Pelati, G. Patriarche, O. Mauguin, L. Largeau, L. Travers, et al.. GaAs (1 1 1) epilayers grown by MBE on Ge (1 1 1): Twin reduction and polarity. Journal of Crystal Growth, 2019, 519, pp.84-90. ⟨10.1016/j.jcrysgro.2019.05.006⟩. ⟨hal-02351877⟩