2016/05/11 by Takaki Onozato, Takayoshi Katase, Akira Yamamoto +5 · 2 citations
Engineering · Materials Science · Chemistry · #Semiconductor materials and devices #Transition Metal Oxide Nanomaterials #ZnO doping and properties #Amorphous solid #Valence (chemistry) #Niobium oxide #Niobium #Optoelectronics #Oxygen #Oxide #Materials science #Electrical resistivity and conductivity #Thin film #Ion #Chemistry #Nanotechnology #Crystallography #Metallurgy #Electrical engineering
paper · doi:10.1088/0953-8984/28/25/255001
openalex publication_date 2016/05/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
In order to understand the optoelectronic properties of amorphous niobium oxide (a-NbO x ), we have investigated the valence states, local structures, electrical resistivity, and optical absorption of a-NbO x thin films with various oxygen contents. It was found that the valence states of Nb ion in a-NbO x films can be controlled from 5+ to 4+ by reducing oxygen pressure during film deposition at room temperature, together with changing the oxide-ion arrangement around Nb ion from Nb2O5-like to NbO2-like local structure. As a result, a four orders of magnitude reduction in the electrical resistivity of a-NbO x films was observed with decreasing oxygen content, due to the carrier generation caused by the appearance and increase of an oxygen-vacancy-related subgap state working as an electron donor. The tunable optoelectronic properties of a-NbO x films by valence-state-control with oxygen-vacancy formation will be useful for potential flexible optoelectronic device applications.