Controlling the p-Type Conductivity and Composition Range for Bipolar Conduction in Ni_xCd_1–xO Alloys by Acceptor Doping

Abstract

Oxide-based transparent p−n homojunctions are desirable for the development of transparent electronics. However, most oxide semiconductors are intrinsically n-type and to achieve p-type wide-gap oxide is still challenging. Previously, we have demonstrated that alloying a high-mobility n-type material such as CdO with p-type NiO can provide an avenue for electronic band engineering and consequently achieve bipolar conductivity in the midalloy composition. In this study, we synthesized O-rich Ni x Cd 1−x O alloys (Ni x Cd 1−x O 1+δ ) over the entire composition with Li and Cu doping using radio frequency (RF) magnetron sputtering at room temperature. We show that by Li and Cu doping the conductivity in the p-type regime of these alloys is improved, which also leads to a wider composition window for bipolar doping in Ni x Cd 1−x O. Specifically, by Li doping, the p-type alloy composition can be extended to x ≥ 0.3 so that the bipolar doping window is expanded to 0.30 ≤ x ≤ 0.52. Detailed measurements on electrical, structural, optical, and electronic properties suggest that Li is an effective acceptor, offering a promising way to improve the p-type conduction in Ni-rich Ni x Cd 1−x O alloys as well as to regulate the bipolar conductivity in this alloy system. A p-Ni 0.7 Cd 0.3 O:Li/n-Ni 0.45 Cd 0.55 O quasi-homojunction was fabricated and a rectification ratio ∼10 2 with an ideality factor of ∼2.9 was obtained. The demonstrated quasi-homojunction structure also showed >60% transmittance in the visible spectrum.

Improving the p-Type Conductivity and Transparency of Pure Phase SnO by Ga and Na Doping

“…Figure shows the temperature dependent electrical properties of (a) undoped SnO, (b) ∼3.2% Na-doped, and (c) ∼1.2% Ga-doped SnO. All samples show an increase of 2–3 orders of magnitude in p with increasing temperature from 80 to 500 K. On the other hand, below ∼350 K, μ increases with decreasing T , which is in stark contrast to the small polaron hopping (SPH) conduction in NiO and related alloys, − but consistent with the reduced phonon scattering at low temperature. Figure d shows the Arrhenius plots of the hole concentration of the 3 samples.…”

“…In particular, the film with ∼2.3% Na has a T vis of ∼50%, possibly due to the presence of excess Sn clusters as discussed above. It is worth noting that for p-type wide gap oxides such as NiO, T vis is typically rather low (in the range of 40 to 60%), 39,40 presumably due to the presence of Ni vacancies. 44 Hence, the T vis for our highly conducting SnO can be considered as relatively high among p-type oxides.…”

Chemical vapor deposition growth and photodetector performance of lead-free all-inorganic crystalline Cs3Sb2X9 (X = I, Br) perovskite thin films

“…Several Tauc-Lorentz oscillators were then applied to readjust the dielectric function according to the previous report. 60 Photodetector fabrication Cs 3 Sb 2 X 9 films were first deposited on a cleaned glass substrate by the above discussed CVD method. Au electrodes of B40 nm thick were then deposited over the films using a shadow mask (Ni grids, 300 mesh) by thermal evaporation.…”

Two-Step Chemical Vapor Deposition-Synthesized Lead-Free All-Inorganic Cs3Sb2Br9 Perovskite Microplates for Optoelectronic Applications

“…Regression analysis was applied to achieve the best fitting for the experimental data. A parametric model dielectric function composed of several Tauc–Lorentz models was then used to parameterize the dielectric function similar to the procedure used in the report …”

“…A parametric model dielectric function composed of several Tauc− Lorentz models was then used to parameterize the dielectric function similar to the procedure used in the report. 69 Photodetector Fabrication. The photoconductive devices were fabricated on individual Cs 3 Sb 2 Br 9 perovskite microplates.…”