Room temperature ferromagnetism in (Ga1−xMnx)2O3 epitaxial thin films

Guo, Daoyou; Wu, Zhenping; An, Yarui; Li, Xiaojiang; Guo, Xuncai; Chu, Xuan; Sun, Changlong; Lei, Ming; Li, Linghong; Cao, Lixin; Li, Peigang

doi:10.1039/c4tc02833c

Cited by 84 publications

(69 citation statements)

References 34 publications

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“…The cross-sectional elemental mapping was conducted over 10 places; thereby no clear separated phase or metal agglomerated areas were confirmed. It is consistent with the secondary ion mass spectrometry (SIMS) depth profiling in our previous report23, indicating that Mn is actually uniformly distributed. The interface microstructure between the Ga 2 O 3 film and the Al 2 O 3 substrate were also explored [Fig.…”

Section: Resultssupporting

confidence: 91%

Inhibition of unintentional extra carriers by Mn valence change for high insulating devices

Guo

et al. 2016

Sci Rep

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For intrinsic oxide semiconductors, oxygen vacancies served as the electron donors have long been, and inevitably still are, attributed as the primary cause of conductivity, making oxide semiconductors seem hard to act as high insulating materials. Meanwhile, the presence of oxygen vacancies often leads to a persistent photoconductivity phenomenon which is not conducive to the practical use in the fast photoelectric response devices. Herein, we propose a possible way to reduce the influence of oxygen vacancies by introducing a valence change doping in the monoclinic β-Ga 2 O 3 epitaxial thin film. The unintentional extra electrons induced by oxygen vacancies can be strongly suppressed by the change valence of the doped Mn ions from +3 to +2. The resistance for the Mn-doped Ga 2 O 3 increases two orders of magnitude in compared with the pure Ga 2 O 3 . As a result, photodetector based on Mn-doped Ga 2 O 3 thin films takes on a lower dark current, a higher sensitivity, and a faster photoresponse time, exhibiting a promising candidate using in high performance solar-blind photodetector. The study presents that the intentional doping of Mn may provide a convenient and reliable method of obtaining high insulating thin film in oxide semiconductor for the application of specific device.The intrinsic semiconductors always exhibit unintentional n-or p-type conductivity induced by native defects such as vacancies or interstitials 1,2 , leading to a difficulty in achieving high insulating material and limiting their use in the specific devices such as photodetector, dielectric layer, etc. In particular, for oxide semiconductors, the conductivity is often seen to exhibit a pronounced dependence on partial pressure of oxygen during growth 3,4 . It seems logical, that this conductivity is related to the presence of oxygen vacancies which served as the electron donors leading to a decrease in resistivity, as has been assumed for many years. In fact, with recent advances in growth techniques, particularly perhaps the advent of novel schemes of molecular beam epitaxy, it has become possible to grow thin films of oxide materials, as required for device applications, with rather high structural quality [5][6][7] . Notwithstanding this, however, oxygen vacancies have long been 6-8 , commonly and inevitably still are, attributed as the primary cause of conductivity in oxide semiconductors. Meanwhile, the presence of oxygen vacancies in oxides often leads to a persistent photoconductivity phenomenon since the carriers trapped by oxygen vacancies have longer lifetime and drift back to their original states slowly 9,10 . It is not conducive to the practical use in the fast photoelectric response devices. Take ZnO based photodetector as an example, the response time would extend to the order of minutes or hours due to the presence of oxygen vacancies 9,10 . In this work, we propose a possible way to suppress the unintentional extra carriers which are induced by oxygen vacancies and reduce the influence of oxygen vacancies by introducing...

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Section: Resultssupporting

confidence: 91%

Inhibition of unintentional extra carriers by Mn valence change for high insulating devices

Guo

et al. 2016

Sci Rep

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“…For Ga 2 O 3 , n=2. The bandgap obtained by extrapolating the linear region of the plot (αhν) 2 versus hν, as shown in Fig. 3(b).…”

Section: B Xps Analysismentioning

confidence: 99%

“…Until now, Ga 2 O 3 was revealed to have six different crystalline phases, including α-, β-, γ-, δ-, ε-, and κ-Ga 2 O 3 . [1][2][3][4][5][6] Among them, the monoclinic structured β-Ga 2 O 3 is the most stable form at room temperature. All other phases could be converted to β-Ga 2 O 3 after heated to 1000 • C or above.…”

Section: Introductionmentioning

confidence: 99%

Stabilization and enhanced energy gap by Mg doping in ε-phase Ga2O3 thin films

Huang

et al. 2018

AIP Advances

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Mg-doped Ga2O3 thin films with different doping concentrations were deposited on sapphire substrates using laser molecular beam epitaxy (L-MBE) technique. X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-vis) absorption spectrum were used to characterize the crystal structure and optical properties of the as-grown films. Compared to pure Ga2O3 thin film, the Mg-doped thin films have transformed from the most stable β-phase into ε-phase. The absorption edge shifted to about 205 nm and the optical bandgap increased to ∼ 6 eV. These properties reveal that Mg-doped Ga2O3 films may have potential applications in the field of deep ultraviolet optoelectronic devices, such as deep ultraviolet photodetectors, short wavelength light emitting devices and so on.

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“…[1][2][3][4][5][6] As a binary metal oxide, gallium oxide, with a wide band gap of $4.9 eV, is considered as one of ideal candidates for RRAM because of its intrinsic high resistance characteristic and extraordinarily sensitive conductivity to the oxygen. [7][8][9] In recent years, reversible bipolar resistance switching behaviors in gallium oxide thin films were obtained and investigated. [10][11][12][13][14] For instance, Gao et al investigated the effect of top electrode materials on bipolar resistive switching behavior of gallium oxide films and pointed out that the migration of oxygen vacancies in the vicinity of the electrode area plays an important role in the resistive switching process.…”

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Unipolar resistive switching behavior of amorphous gallium oxide thin films for nonvolatile memory applications

Guo

et al. 2015

Applied Physics Letters

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Amorphous gallium oxide thin film with heavy oxygen deficiency was deposited on Pt/Ti/SiO2/Si substrate by pulsed laser deposition in order to explore the resistive switching behavior of the Pt/Ga2O3-x/Pt sandwich structure. A well unipolar resistive switching behavior was obtained in this structure, which exhibits a high resistance ratio of OFF/ON up to 104, non-overlapping switching voltages, and excellent repeatability and retention. Both I-V relation plots of ON and OFF states and temperature dependent variation resistances indicate that the observed resistive switching behavior can be explained by the formation/rupture of conductive filaments formed out of oxygen vacancies.

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Room temperature ferromagnetism in (Ga_1−xMn_x)₂O₃ epitaxial thin films

Abstract: Mn-doped monoclinic β-(Ga1−xMnx)2O3 thin films were epitaxially grown on α-Al2O3 (0001) substrates by alternately depositing Ga2O3 and Mn layers using the laser molecular beam epitaxy technique.

Cited by 84 publications

References 34 publications

Inhibition of unintentional extra carriers by Mn valence change for high insulating devices

Inhibition of unintentional extra carriers by Mn valence change for high insulating devices

Stabilization and enhanced energy gap by Mg doping in ε-phase Ga2O3 thin films

Unipolar resistive switching behavior of amorphous gallium oxide thin films for nonvolatile memory applications

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