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HL: Fachverband Halbleiterphysik
HL 30: Poster I
HL 30.13: Poster
Dienstag, 17. März 2020, 13:30–15:45, P3
The influence on defect states in Aluminium oxide on conductivity of a hydrogen-terminated diamond surface — •Dennis Oing, Jens Kerski, Nicolas Wöhrl, Martin Geller, and Axel Lorke — Faculty of Physics and CENIDE, University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany
Hydrogen-terminated diamond shows a surface conductivity induced by transfer doping by acceptor states in adsorbate layers. Hence, the thermal and longtime stability of such devices is usually low. When covered with metal oxides, e.g. Al2O3 or MoO3 a functionalized diamond surface show a higher thermal stability of reduced to 500∘C due to not desorption of mentioned acceptor states.
In this study, defects in Al2O3-layers are used as acceptors on hydrogen-terminated diamond. These states are characterized using time-resolved charging and discharging of the defects by optical illumination using an UV-LED.
Temperature dependent Hall measurements show that the carrier density of the 2DHG induced by adsorbates from air is 1.3× 10−13 cm−2, while it is 6.7× 10−12 cm−2 with Al2O3 coverage. Carrier density is temperature independent in both cases. After illumination with an UV-LED, the conductivity of the 2DHG increases by 11 % at room temperature and 2.6 % at 200 K. The excitation shows 3 distinct time constants between 41 s and 40 min at room temperature. It is suggested that the transfer of electrons to the defect states is a three step process.