Vol.:(0123456789) 1 3
Journal of Materials Science: Materials in Electronics
https://doi.org/10.1007/s10854-019-01950-5
Low temperature synthesis of α‑ and β‑phase Bi
2
O
3
thin film via B
doping: tailoring optical band gap and n‑ to p‑type Bi
2
O
3
Bidhan Chandra Dev
1
· Majibul Haque Babu
1,4
· Jiban Podder
1
· Suresh Sagadevan
2
· Abdullah Zubair
3
Received: 20 May 2019 / Accepted: 29 July 2019
© Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract
In this article, we fabricated p-type bismuth oxide (Bi
2
O
3
) thin films with tailoring optical band gap by boron (B) doping,
for the first time. In addition, an effort is made to see the influence of B doping on the surface morphological, structural,
optical and electrical transport properties of Bi
2
O
3
thin films. Field Emission Scanning Electron Microscope (FESEM)
images demonstrated that the film surface is covered by well-defined multigonal shaped particles and glassy surface. α-Bi
2
O
3
(monoclinic) and β-Bi
2
O
3
(tetragonal) phase structures are confirmed by X-ray diffraction (XRD) analysis. The average
crystallite size is decreased from 46.62 to 23.57 nm with B doping concentration. Moreover, the average strain, stress and
dislocation density values are calculated using XRD data. The optical band gaps have changed from 3.70 to 3.99 eV with the
texture coefficient values of
(
11
2
)
orientation plane. A minimum refractive index and optical conductivity value are found
to be 2.58 and 2.23 × 10
6
Ω
−1
m
−1
for 3 at.% B content. Electrical parameters, viz. resistivity, sheet resistance, charge carrier
concentration, mobility and conductivity types are investigated using a van der Pauw Hall measurement system. Electrical
measurements demonstrated that the resistivity values are found to vary in the range of 1.23–1.82, × 10
3
Ω-m with increasing
B doping concentrations. A high-quality factor is obtained 5.52 × 10
−6
Ω
−1
for higher doping content at 550 nm wavelength.
This work promotes a new vision into the fabrication of p-type Bi
2
O
3
thin films and facilitates their application in the field
of optoelectronic devices, viz. window layer coating, p–n junction and photovoltaic applications.
1 Introduction
Now-a-days, nanostructured bismuth oxide (Bi
2
O
3
) thin
films have given much interest of research due to unique
characteristics such as high optical energy band gap (~ 2
to 3.96 eV), high refractive index, dielectric permittiv-
ity, transparency, mechanical strength, as well as marked
photoluminescence and photoconductivity [1–4]. These
unique properties make Bi
2
O
3
a promising candidate for
several applications, e.g., solar cell, optoelectronics, optical
coatings, fuel cell, gas sensors, ceramic glass manufactur-
ing, blue laser recording, as well a high-T
c
superconduc-
tors [5–7]. Generally, Bi
2
O
3
reveals six crystallographic
phases’ viz. α-Bi
2
O
3
(monoclinic), β-Bi
2
O
3
(tetragonal),
γ-Bi
2
O
3
(body centered cubic), δ-Bi
2
O
3
(face centered
cubic), ε-Bi
2
O
3
(orthorhombic) and ω-Bi
2
O
3
(triclinic) [8].
Among these phases, α-Bi
2
O
3
and β-Bi
2
O
3
has a precise
interest. In general, α-Bi
2
O
3
is stable at relatively low tem-
perature (~ 730 °C) with a wide optical band gap of about
3.00 eV. Furthermore, α-Bi
2
O
3
phase exhibits a high refrac-
tive index and makes it a promising candidate for nonlinear
optical devices such as optical switch, wavelength converters
and ultra-short pulse generators, etc., [9, 10]. On the other
hand, β-Bi
2
O
3
has a tremendous performance in photoelec-
trochemical and photocatalytic property [11]. Therefore,
α-Bi
2
O
3
and β-Bi
2
O
3
nanostructure thin film reveals excel-
lent optoelectronic property [12].
In the recent years, Bi
2
O
3
has been investigated in the
form of amorphous thin films, ceramics, or nanostruc-
tures [13]. The nanostructure Bi
2
O
3
thin films have been
synthesized using various techniques viz chemical vapor
deposition (CVD), pulse laser deposition (PLD), sputtering,
* Jiban Podder
jpodder59@gmail.com
1
Department of Physics, Bangladesh University
of Engineering and Technology, Dhaka 1000, Bangladesh
2
Nanotechnology and Catalysis Research Center, University
of Malaya, 50603 Kuala Lumpur, Malaysia
3
Department of Glass and Ceramics Engineering, Bangladesh
University of Engineering and Technology, Dhaka 1000,
Bangladesh
4
Basic Science Division, World University of Bangladesh,
Dhaka 1205, Bangladesh