Wang, Ying
[Verfasser:in];
Kwok, Cheuk Kai Gary
[Verfasser:in];
Xiao, Dezhi
[Verfasser:in];
Zhu, Jiuzhou
[Verfasser:in];
Shu, Xingyu
[Verfasser:in];
Liu, Chao Ping
[Verfasser:in];
Man Yu, Kin
[Verfasser:in]
Improving the P–Type Conductivity of Cu2o Thin Films by Ni Doping and Their Heterojunction with N–Zno
Beschreibung:
Cu2O is one of the few transition metal oxides which can exhibit p–type conductivity due to native acceptor defects. Further improvements in p–type conductivity of Cu2O can be achieved via extrinsic doping and post–growth processing. In this work, we investigate the effects of Ni doping in Cu2O with Ni content up to ~11%, and find that the incorporation of Ni improves the p–type conductivity of the films without altering the Cu2O crystallographic structure and maintains a wide bandgap of 2.5 eV. Significant improvement in the crystallinity as well as the p–type conductivity of the alloy films can be observed after rapid thermal annealing (RTA). In particular, alloys with x≥0.005 exhibit a high hole mobility µ~12–22 cm2/V-s with resistivity of ρ~30–60 Ω-cm and free hole concentration N~1×1016 cm-3 after RTA in air–N2 ambient at 700°C. Such improvement can be attributed to the formation of Cu vacancies which promotes Ni substitution in the presence of small amount O2 in the air–N2 annealing environment. Finally,a p–(NixCu1-x)2O/n–ZnO heterojunction was fabriacted and and exhibits both rectification and photovoltaic response. XPS measurements reveal a type II band offset of this heterojunction with valence band and conduction band offsets of 2.81 eV and 2.07 eV, respectively