Abstract:
Carrier suppression without deteriorating the carrier mobility is a key challenge in metal like
carrier density of amorphous transparent conducting oxide (TCO) thin films for next-generation
flexible optoelectronic device applications. Here, we studied the role of oxygen for confining the
behavior of boron dopant as a carrier suppressor and as a carrier donor in amorphous indiumzinc-oxide (a-IZO) thin films. The carrier density of amorphous IZO thin film was reduced to the
order of ∼1016 cm−3 with carrier mobility of ∼9 cm2
/Vs by precisely controlling the boron and
oxygen content in BIZO thin films. The electrical properties revealed that boron requires an extra
presence of oxygen to activate its carrier suppressant nature. Structural and defects chemistry in
IZO and BIZO thin films were studied by X-ray diffraction (XRD), Photoluminescence (PL) and
X-ray photoelectron spectroscopy (XPS). The XRD confirmed the amorphous nature of IZO and
BIZO while PL and XPS results suggested the presence of less defects in BIZO in contrast to the
IZO films, which is a prerequisite criterion to choose the oxide thin film for transistors and fast
switching device applications. The post deposition annealing of IZO and BIZO thin film in air
confirmed the better thermal stability of BIZO over IZO thin film. In the perspective of
experimental verification, the photo-persistent current with time measurement showed a relevant
evidence of less concentration of oxygen vacancies in BIZO thin films by exhibiting the small
decay time as compared to IZO thin films. This study proposes the appropriate use of B as a
carrier donor and a carrier suppressor in IZO matrix as a robust, reliable and thermally stable
active layer for next-generation flexible and stable electronic device applications.
