Preparation of ferroelectric field effect transistor based on sustainable strongly correlated (Fe,Zn)3O4 oxide semiconductor and their electrical transport properties

Abstract

We have constructed a field effect transistor structure composed of the sustainable oxide semiconductor ͑Fe, Zn͒ 3 O 4 with high Curie temperature and ferroelectric Pb͑Zr, Ti͒O 3 . Electric field control of ͑Fe 2.5 Zn 0.5 ͒O 4 channel resistance was achieved in the heterostructures though modulation of their carrier concentration. The results will lead to the significant development of sustainable oxide semiconductor spintronics devices working at room temperature.Field effect control of transition metal oxides with strongly correlated oxide in heterostructures offer to opportunities create next generation functional electrics devices, 1 such as electrically tunable colossal magnetoresistance devices, 2,3 ferromagnet, 4 and high T C superconductor 5 with controlling interactions between charge with spin. Another aspect of oxide is "sustainability," namely, a strategy for the use of elemental natural resources with environmental friendliness, which is an indispensable for the development of advanced materials and devices concerning our global environment. Among them, Fe-based oxides with spinel structures ͑spinel ferrites͒ exhibit ferrimagnetism with a very high Curie temperatures exceeding 800 K, which are industrially used for making recording media as an insulating ferrimagnet. The solid solution system of spinel ferrite, Fe 3−x Zn x O 4 ͑0 Ͻ x Ͻ 1͒, is a good candidate not only as a magnetic semiconductor with high T C ͑Refs. 6 and 7͒ but also as a an sustainable electromagnetic material. Their component, namely, Fe 2 O 3 and ZnO, have abilities concerning sustainability from the point of view on rich natural resource and environmental friendliness. For example, the Clarke number of Fe is the fourth and Zn is alterative element for rare In. Moreover, the powders of Fe 2 O 3 and ZnO are widely used for cosmetic applications. These are high advantages in comparison with other spin related field effect devices.Here, we report fabrication of ferroelectric field effect transistor ͑FET͒ structure based on sustainable strongly correlated ͑Fe, Zn͒ 3 O 4 ͑FZO͒ oxide semiconductor and their electrical transport properties.The FZO/PZT heterostructure for a bottom-gate FET was prepared on a Nb͑1 wt %͒-doped SrTiO ͑Nb-STO͒ ͑100͒ single crystal substrate by pulsed-laser deposition ͑PLD͒ technique. A Nb-STO͑100͒ substrate was used as a bottom electrode. A PZT layer was deposited as a ferroelectric gate insulator by PLD at oxygen pressure ͑P O2 ͒ of 6.0 Pa and substrate temperature ͑T s ͒ of 550°C. The thickness of PZT was fixed to 300 nm. A FZO as a channel layer was deposited on a PZT layer by PLD at P O2 of 1.0ϫ 10 −3 Pa and T s of 320°C during the deposition. The deposited thickness ͑d͒ of FZO was set to 20 nm. Finally, Au as a top electrode was prepared by thermal deposition technique. The channel size was 200ϫ 500 m. The ferroelectric property was evaluated by using a dielectric polarization measurement system. For the physical properties of FZO thin films, Hall resistance was measured at room temperature under a magnet...

Nanoscale study of perovskite BiFeO3/spinel (Fe,Zn)3O4 co-deposited thin film by electrical scanning probe methods

“…(Fe,Zn) 3 O 4 (FZO) is a promising candidate for its integration with BFO due to his high oxidative resistance. It is also a carrier-tunable magnetic semiconductor [9] with a high Curie temperature above room temperature [10]. C-AFM technique has already been proven to be useful for the characterization of this material such as FZO nanodots [11].…”

Self-Assembled Growth of Spinel (Fe,Zn)3O4–Perovskite BiFeO3 Nanocomposite Structures Using Pulsed Laser Deposition

“…Transition metal oxides display attractive spin-related electronic properties such as high Curie temperature, possible perfect spin-polarization, and colossal magnetoresistance, and much attention has been paid to the use of the respective heterostructures as ferromagnetic field-effect transistors, [1][2][3][4] diodes, 5) and tunneling magnetoresistance devices. 6) A recent breakthrough in oxide nanofabrication techniques has been reported by Zheng et al: 7) the selfassembled growth of nanoscaled heterojunctions typically involving nanocomposite structures of perovskite BaTiO 3spinel CoFe 2 O 4 .…”

“…Compared with Fe 3 O 4 , partially Znsubstituted Fe 3 O 4 , namely (Fe,Zn) 3 O 4 , has high oxidative resistance and is a carrier-tunable magnetic semiconductor with a high Curie temperature above room temperature. 2,15) In this research, we have tried to obtain nanocomposite thin films comprising the (Fe,Zn) 3 O 4 (FZO) and ferroelectric BiFeO 3 (BFO) by the self-assembled growth method, and successfully obtained nano-composite oxide thin films with spintronic materials.…”

Unstrained Epitaxial Zn-Substituted Fe3O4 Films for Ferromagnetic Field-Effect Transistors

“…In our previous study, by fabricating a ferroelectric Pb(Zr,Ti)O 3 bottom-gate FET, we controlled the conductivity of a Zn-substituted Fe 3 O 4 (Fe 2:5 Zn 0:5 O 4 ) film. 12) The field-effect mobility FE was, however, found to be very low, 8:1 Â 10 À4 cm 2 V À1 s À1 ; carriers doped by the field effect only slightly modified the channel conductivity. During the course of optimizing the device structure, we found that the lattice mismatch between Fe 2:5 Zn 0:5 O 4 (lattice constant: a A) with a mismatch of $8% showed one order of magnitude lower conductivity than a film prepared on a lattice-matched MgO(001) substrate (2a MgO ¼ 8:422 A).…”

“…The device exhibited typical n-type behavior, as reported previously for Fe 2:5 Zn 0:5 O 4 /Pb(Zr,Ti)O 3 devices. 12) Figure 3(a) displays the dependence of the drain-source current I D on the gate voltage V G measured for a sample with W ¼ 30 m. V G was applied such that the gate leakage current did not exceed 0.2 nA, while the drain-source voltage V D was fixed at 10 V. The application of a positive (negative) V G induces the accumulation (exhaustion) of electrons at the surface of Fe 2:5 Zn 0:5 O 4 , resulting in an increase (a decrease) in I D , i.e., conductivity. From the slope of the I D -V G curve, FE was estimated to be 1:2 Â 10 À2 cm 2 V À1 s À1 using the general relation,…”