Schottky barrier parameters and low frequency noise characteristics of graphene-germanium Schottky barrier diode

Khurelbaatar, Zagarzusem; Kil, Yeon‐Ho; Shim, Kyu–Hwan; Cho, Hyunjin; Kim, Myung-Jong; Lee, Sung‐Nam; Jeong, Jae-chan; Hong, Hyobong; Choi, Chel‐Jong

doi:10.1016/j.spmi.2016.01.029

Cited by 15 publications

(6 citation statements)

References 28 publications

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“…The series resistance parameter, R s , fluctuates approximately by a factor of three among the devices within the range 10 5 to 10 6 Ω and is of the order of the resistance measured on the continuous graphene film outside the LO pattern. As expected, the values of the R s parameter of our devices are quite larger than those fabricated by graphene transfer and conventional lithography, in which large-area (of the order of 10 –2 cm 2 ) Ohmic contacts to graphene are realized , (see also Section S3 of the Supporting Information). Even though our devices are obtained on the same sample and measurements are performed with the same C-AFM tip, the variability of R s values confirms that the differences in the local tip–graphene electrical contact can affect the data depending on the specific collection condition of each single I – V curve.…”

Section: Results and Discussionsupporting

confidence: 69%

“…However, device fabrication using epitaxial graphene on Ge is still at an early stage and SB junctions fabricated on such a system are missing up till now. In fact, as in the case of silicon, only graphene/Ge SB junctions involving graphene transfer have been realized − to date. In this framework, the fabrication and characterization of SB devices based on metal-free graphene is not only of paramount importance for application purposes, but also represents a critical milestone in order to assess the device performance loss due to the use of transferred metal-catalysed graphene.…”

Section: Introductionmentioning

confidence: 99%

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Submicron Size Schottky Junctions on As-Grown Monolayer Epitaxial Graphene on Ge(100): A Low-Invasive Scanned-Probe-Based Study

Pea

Seta

Gaspare

et al. 2019

ACS Appl. Mater. Interfaces

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We report on the investigation of the Schottky barrier (SB) formed at the junction between a metal-free graphene monolayer and Ge semiconductor substrate in the as-grown epitaxial graphene/Ge(100) system. In order to preserve the heterojunction properties, we defined submicron size graphene/Ge junctions using the scanning probe microscopy lithography in the local oxidation configuration, a low-invasive processing approach capable of inducing spatially controlled electrical separations among tiny graphene regions. Characteristic junction parameters were estimated from I–V curves obtained using conductive-atomic force microscopy. The current–voltage characteristics showed a p-type Schottky contact behavior, ascribed to the n-type to p-type conversion of the entire Ge substrate due to the formation of a large density of acceptor defects during the graphene growth process. We estimated, for the first time, the energy barrier height in the as-grown graphene/Ge Schottky junction (φB ≈ 0.45 eV) indicating an n-type doping of the graphene layer with a Fermi level ≈ 0.15 eV above the Dirac point. The SB devices showed ideality factor values around 1.5 pointing to the high quality of the heterojunctions.

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Section: Results and Discussionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Submicron Size Schottky Junctions on As-Grown Monolayer Epitaxial Graphene on Ge(100): A Low-Invasive Scanned-Probe-Based Study

Pea

Seta

Gaspare

et al. 2019

ACS Appl. Mater. Interfaces

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“…The growth of graphene on silicon is problematic due to the formation of carbides; therefore, germanium (Ge) was investigated as an alternative substrate due to its catalytic activity and non-reactivity toward carbon. − It has been shown that wafer-sized graphene can be grown on Ge by chemical vapor deposition (CVD) with high carrier mobility (up to 7250 cm 2 /V·s), which make this system promising for microelectronic applications. Indeed, the graphene/Ge system has been proposed for several device applications, such as Schottky barrier junction-based photodiodes, hybrid photodetectors, and so forth. − …”

Section: Introductionmentioning

confidence: 99%

Investigation of the Oxidation Behavior of Graphene/Ge(001) Versus Graphene/Ge(110) Systems

Akhtar

Dąbrowski

Lisker

et al. 2020

ACS Appl. Mater. Interfaces

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The oxidation behavior of Ge(001) and Ge(110) surfaces underneath the chemical vapor deposition (CVD)-grown graphene films has been investigated experimentally and interpreted on the basis of ab initio calculations. Freshly grown samples were exposed to air for more than 7 months and periodically monitored by X-ray photoelectron spectroscopy, scanning electron microscopy, and Raman spectroscopy. The oxidation of Ge( 110) started with incubation time of several days, during which the oxidation rate was supposedly exponential. After an ultrathin oxide grew, the oxidation continued with a slow but constant rate. No incubation was detected for Ge(001). The oxide thickness was initially proportional to the square root of time. After 2 weeks, the rate saturated at a value fivefold higher than that for Ge(110). We argue that after the initial phase, the oxidation is limited by the diffusion of oxidizing species through atomic-size openings at graphene domain boundaries and is influenced by the areal density and by the structural quality of the boundaries, whereby the latter determines the initial behavior. Prolonged exposure affected the surface topography and reduced the strain in graphene. In the last step, both the air-exposed samples were annealed in vacuum at 850 °C. This removed oxygen from the substrate and restored the samples to their initial state. These findings might constitute an important step toward further optimization of graphene grown on Ge.

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“…Such noise behavior is typical for diode devices and has previously been observed for other diode technologies. [ 33,38,39 ] Interestingly, S I (I) dependence becomes closer to quadratic, S I –I 2 , at 380 K. The quadratic behavior is expected for linear resistors and can also be found in diodes in certain transport regimes. [ 34,35,40,41 ] Figure 4b shows the normalized noise spectral density, S I /I 2 , at f = 10 Hz as a function of temperature for different currents.…”

Section: Resultsmentioning

confidence: 86%

Temperature Dependence of Low‐Frequency Noise Characteristics of NiO_x/β‐Ga₂O₃ p–n Heterojunction Diodes

Ghosh,

Mudiyanselage,

Kargar

et al. 2023

Adv Elect Materials

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Temperature dependence of the low‐frequency electronic noise in NiOx/β‐Ga2O3 p–n heterojunction diodes is reported. The noise spectral density is of the 1/f‐type near room temperature but shows signatures of Lorentzian components at elevated temperatures and at higher current levels (f is the frequency). It is observed that there is an intriguing non‐monotonic dependence of the noise on temperature near T = 380 K. The Raman spectroscopy of the device structure suggests material changes, which results in reduced noise above this temperature. The normalized noise spectral density in such diodes is determined to be on the order of 10−14 cm2 Hz−1 (f = 10 Hz) at 0.1 A cm−2 current density. In terms of the noise level, NiOx/β‐Ga2O3 p–n diodes perform excellently for new technology and occupy an intermediate position among devices of various designs implemented with different ultra‐wide‐bandgap semiconductors. The obtained results are important for understanding the electronic properties of NiOx/β‐Ga2O3 heterojunctions and contribute to the development of noise spectroscopy as the quality assessment tool for new electronic materials and device technologies.

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Schottky barrier parameters and low frequency noise characteristics of graphene-germanium Schottky barrier diode

Cited by 15 publications

References 28 publications

Submicron Size Schottky Junctions on As-Grown Monolayer Epitaxial Graphene on Ge(100): A Low-Invasive Scanned-Probe-Based Study

Submicron Size Schottky Junctions on As-Grown Monolayer Epitaxial Graphene on Ge(100): A Low-Invasive Scanned-Probe-Based Study

Investigation of the Oxidation Behavior of Graphene/Ge(001) Versus Graphene/Ge(110) Systems

Temperature Dependence of Low‐Frequency Noise Characteristics of NiO_x/β‐Ga₂O₃ p–n Heterojunction Diodes

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Schottky barrier parameters and low frequency noise characteristics of graphene-germanium Schottky barrier diode

Cited by 15 publications

References 28 publications

Submicron Size Schottky Junctions on As-Grown Monolayer Epitaxial Graphene on Ge(100): A Low-Invasive Scanned-Probe-Based Study

Submicron Size Schottky Junctions on As-Grown Monolayer Epitaxial Graphene on Ge(100): A Low-Invasive Scanned-Probe-Based Study

Investigation of the Oxidation Behavior of Graphene/Ge(001) Versus Graphene/Ge(110) Systems

Temperature Dependence of Low‐Frequency Noise Characteristics of NiOx/β‐Ga2O3 p–n Heterojunction Diodes

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Product

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Temperature Dependence of Low‐Frequency Noise Characteristics of NiO_x/β‐Ga₂O₃ p–n Heterojunction Diodes