TY - JOUR
T1 - Tuning phase fractions and leakage properties of chemical solution deposition-derived mixed-phase BiFeO3 thin films
AU - Zhou, Jinling
AU - Sando, Daniel
AU - Cheng, Xuan
AU - Ma, Zhijun
AU - Valanoor, Nagarajan
AU - Zhang, Qi
PY - 2020/12/9
Y1 - 2020/12/9
N2 - Phase-pure epitaxial bismuth ferrite (BiFeO3, BFO) thin films with a homogeneous mixed-phase structure were synthesized on (001)-oriented lanthanum aluminate (LaAlO3, LAO) substrates using chemical solution deposition. The phase development of the BFO thin film and its leakage current characteristics have been systematically investigated as a function of thickness (number of spin-coated layers) and the heat treatment process (heating temperature and dwell time). The results show that the tetragonal-like (T′) phase fraction changes dramatically from 35% (45 nm thick single layer) to 10% (250 nm thick four-layer films). In a two-layer film (80 nm) configuration, the T′-phase fraction was further tuned. When annealing at 640 °C for 30 min, this mixed-phase BFO film, despite its high T′-phase fraction (28%), shows the lowest leakage current (<0.1 A/cm2 at <500 kV/cm), comparable to 200 nm pulsed laser deposition-grown pure R-BFO thin films. In contrast to the observed bulk-limited Ohmic or space-charge-limited-conduction (SCLC)-predominant mechanism in pure R′-phase and low T′-phase fraction BFO thin films, the high T′-phase fraction (∼28%) mixed-phase BFO film displays an interface-limited Schottky emission to an SCLC mechanism transition with increasing electric field.
AB - Phase-pure epitaxial bismuth ferrite (BiFeO3, BFO) thin films with a homogeneous mixed-phase structure were synthesized on (001)-oriented lanthanum aluminate (LaAlO3, LAO) substrates using chemical solution deposition. The phase development of the BFO thin film and its leakage current characteristics have been systematically investigated as a function of thickness (number of spin-coated layers) and the heat treatment process (heating temperature and dwell time). The results show that the tetragonal-like (T′) phase fraction changes dramatically from 35% (45 nm thick single layer) to 10% (250 nm thick four-layer films). In a two-layer film (80 nm) configuration, the T′-phase fraction was further tuned. When annealing at 640 °C for 30 min, this mixed-phase BFO film, despite its high T′-phase fraction (28%), shows the lowest leakage current (<0.1 A/cm2 at <500 kV/cm), comparable to 200 nm pulsed laser deposition-grown pure R-BFO thin films. In contrast to the observed bulk-limited Ohmic or space-charge-limited-conduction (SCLC)-predominant mechanism in pure R′-phase and low T′-phase fraction BFO thin films, the high T′-phase fraction (∼28%) mixed-phase BFO film displays an interface-limited Schottky emission to an SCLC mechanism transition with increasing electric field.
KW - Bismuth ferrite
KW - Chemical solution deposition
KW - Leakage conduction mechanism
KW - Mixed phase
KW - Thin film
UR - http://www.scopus.com/inward/record.url?scp=85097808127&partnerID=8YFLogxK
U2 - 10.1021/acsaelm.0c00891
DO - 10.1021/acsaelm.0c00891
M3 - Article
AN - SCOPUS:85097808127
SN - 2637-6113
VL - 2
SP - 4099
EP - 4110
JO - ACS Applied Electronic Materials
JF - ACS Applied Electronic Materials
IS - 12
ER -