Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 9: III-V semiconductors (other than nitrides)

HL 9.2: Vortrag

Montag, 12. März 2018, 15:15–15:30, EW 202

Carbon doping of GaAs grown by molecular beam epitaxy on GaAs(100) and GaAs(111)B — •Alexander Trapp, Tobias Henksmeier, and Dirk Reuter — Optoelektronische Materialien und Bauelemente, Universität Paderborn, 33098 Paderborn, Germany

Bipolar devices, e. g., diodes, require n- as well as p-type doping. In GaAs, a material important for optoelectronic applications, carbon, beryllium, zinc and silicon are possible acceptors. Carbon is especially attractive because of its low diffusivity, very weak amphoteric behavior and high solubility in GaAs. Carbon doping in molecular beam epitaxy (MBE) grown GaAs(100) employing a solid source for carbon is already well studied. However, for GaAs(111)B this has not been studied so far.
In this work we compare the incorporation of carbon into GaAs grown on GaAs(100) and GaAs(111)B with a 1^∘ miscut towards (211). A carbon sublimation source, where a pyrolytic graphite filament is directly heated by an electric current, is used to generate the carbon flux. GaAs layers with carbon concentrations from 10¹⁶ to 10¹⁹ per cm³ have been grown by solid source MBE. The samples are characterized by temperature-dependent Hall measurements using the van-der-Pauw method and photoluminescence spectroscopy. It is shown that the activation energy of the p-dopant found in GaAs(100) and GaAs(111)B are nearly identical. The dependence of free carrier concentration on the surface orientation is weak and will be discussed in detail.