Effects of Ag-doping on the characteristics of Ag_xNi_1-xO transparent conducting oxide film and their applications in heterojunction diodes

Abstract

AgxNi1-xO transparent conducting oxide film with various Ag mole ratios were prepared via a low-cost sol-gel method, and p-AgxNi1-xO/n-Si heterojunction diodes (HJDs) were fabricated. The effects of various Ag mole ratios on the structure, optical, and electrical properties of AgxNi1-xO films were systematically investigated, and their device applications in p-AgxNi1-xO/n-Si HJDs were examined. The Ag atoms accumulate at grain boundaries and inhibit the grain growth of AgxNi1-xO films. The pristine NiO film exhibits a transmittance exceeding 90% for the visible wavelengths. However, transmittance decreases with the Ag mole ratio. A transmittance hollow occurs at approximately 410 nm in Ag-doped AgxNi1-xO film, attributing to the absorption of surface-plasma-resonance of Ag nanoparticles. The energy gap increases from 3.58 to 3.75 eV for the AgxNi1-xO films with the Ag mole ratio of 0 and 1.8, respectively. Hall measurement indicated that the AgxNi1-xO film is p-type. The pristine NiO film exhibits a very high resistivity (≧106 ohm-cm). The resistivity significantly decreases from 14.8 to 1.88 × 10−4 ohm-cm for the AgxNi1-xO film with the Ag mole ratio of 0.3 and 1.8, respectively. Simultaneously, the hole concentration significantly increases from 1.46 × 1016 to 8.03 × 1022 cm−3. X-ray photoelectron spectroscopy revealed the Ni+3/Ni+2 ratio increases from 0.73 to 1.73 for the AgxNi1-xO films with the Ag mole ratio of 0 and 1.8, respectively. The increased Ni+3/Ni+2 ratio is responsible for increase in the hole concentration. The fabricated p-AgxNi1-xO/n-Si HJDs with Ag mole ratio of 0.5 exhibits a clear rectifying behavior with series resistance and ideality factor of 0.88 kΩ and 2.8, respectively.

Silver‐doped nickel oxide as an efficient hole‐transport layer in polymer light‐emitting diodes

“…Figure 4a‐c shows the core‐level Ni 2p 3/2 XPS spectra for NiO:Ag/ITO subjected to calcination at temperatures of 200, 300, and 400°C, respectively. The Ni 2p 3/2 peak was fitted into two distinct peaks, which is in accordance with that reported previously (Hwang et al, 2020; Wei et al, 2018). The peak centered at a low‐binding energy of 853.83 ± 0.06 eV is ascribed to Ni 2+ , which is characteristic for the standard Ni–O bonding configuration in cubic NiO.…”

“…Subsequent XPS measurements were performed to elucidate the conductive mechanism of NiO:Ag films on ITO. with that reported previously (Hwang et al, 2020;Wei et al, 2018).…”

Vacancy defects induced changes in the electronic and optical properties of NiO studied by spectroscopic ellipsometry and first-principles calculations

“…in NiO 31,71,72 . A systematic investigation of the optical properties of NiO combining VNi and these acceptor elements may pave the way to realizing transparent and conducting p-type NiO for transparent electronics applications.…”

“…In our defect modeling, we have adopted one vacant site in each of the magnetic sublattices to preserve the antiferromagnetic symmetry of NiO. in NiO 31,71,72 . A systematic investigation of the optical properties of NiO combining VNi and these acceptor elements may pave the way to realizing transparent and conducting p-type NiO for transparent electronics applications.…”

Electrical Conductivity Studies in Sol–Gel‐Derived Li‐Doped NiO Epitaxial Thin Films

“…A p-type conduction can also be achieved by replacing Ni 2þ with monovalent cations such as Li þ , Cu þ , and Ag þ . [18][19][20][21][22] In that case as well, a Ni 3þ ion is formed by the oxidation of a Ni 2þ ion to preserve electrical neutrality.…”