Investigation of barrier inhomogeneities and interface state density in Au/MgZnO: Ga Schottky contact

Singh, Rohit; Sharma, Pankaj Kumar; Khan, Arif; Garg, Vivek; Awasthi, Vishnu; Kranti, Abhinav; Mukherjee, Shaibal

doi:10.1088/0022-3727/49/44/445303

Cited by 40 publications

(23 citation statements)

References 73 publications

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“…Figure 3a represents the extracted ideality factors and barrier heights of the Pd/Si-based FS-GaN Schottky diodes. It is essential to state that the inhomogeneity of the barrier height in the contact induces the gradient of the barrier height and the ideality factor of the diodes at ~260 K [19,20]. Furthermore, it was found that the drastic increment of current at 260 K in T-I-V curves also supports this behavior.…”

Section: Resultsmentioning

confidence: 98%

Current Transport Mechanism in Palladium Schottky Contact on Si-Based Freestanding GaN

Lee

Ahn

et al. 2020

Nanomaterials

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In this study, the charge transport mechanism of Pd/Si-based FS-GaN Schottky diodes was investigated. A temperature-dependent current–voltage analysis revealed that the I-V characteristics of the diodes show a good rectifying behavior with a large ratio of 103–105 at the forward to reverse current at ±1 V. The interface states and non-interacting point defect complex between the Pd metal and FS-GaN crystals induced the inhomogeneity of the barrier height and large ideality factors. Furthermore, we revealed that the electronic conduction of the devices prefers the thermionic field emission (TFE) transport, not the thermionic emission (TE) model, over the entire measurement conditions. The investigation on deep level transient spectroscopy (DLTS) suggests that non-interacting point-defect-driven tunneling influences the charge transport. This investigation about charge transport paves the way to achieving next-generation optoelectronic applications using Si-based FS-GaN Schottky diodes.

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Section: Resultsmentioning

confidence: 98%

Current Transport Mechanism in Palladium Schottky Contact on Si-Based Freestanding GaN

Lee

Ahn

et al. 2020

Nanomaterials

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“…The organic layer of thickness 80 nm (Figure S3) was spin‐ coated on GZO coated glass before depositing the metal electrode as the top electrode (Figure S3).On top of glass substrate, GZO film was sputtered using DIBS system and employed as the bottom electrode. DIBS system is equipped with radio‐frequency (RF) deposition ion source and direct‐current coupled (DC) assists ion source . As compared to single ion beam deposition, the film stoichiometry is enhanced in DIBS by mixing oxygen into the working gas (Ar) in the assist ion source .…”

Section: Methodsmentioning

confidence: 99%

Benzoselenadiazole‐Based Conjugated Molecules: Active Switching Layers with Nanofibrous Morphology for Nonvolatile Organic Resistive Memory Devices

Jadhav

Kumar

et al. 2020

ChemPlusChem

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In this work, two symmetrical donor-acceptor-donor (D-A-D) type benzoselenadiazole (BSeD)-based π-conjugated molecules were synthesized and employed as an active switching layer for non-volatile data storage applications. BSeD-based derivatives with different donor units attached through common vinylene linkers showed different electrical and optical properties. 4,7-Di ((E)-styryl)benzo[c][2,1,3]selenadiazole (DSBSeD) and 4,7-bis((E)-4-methoxystyryl)benzo[c][2,1,3]selenadiazole (DMBSeD) are sandwiched between gallium-doped ZnO (GZO) and metal aluminum electrodes respectively through solution-processed spin-coating method. The solution-processed nanofibrous switching layer containing the DMBSeD-based memory device showed reliable memory characteristics in terms of write and erase operations with low SET voltage than the randomaggregated DSBSeD-based device. The nanofibrous molecular morphology of switching layer overcomes the interfacial hole transport energy barrier at the interface of the DMBSeD thinfilm and the bottom GZO electrode. The memory device GZO/ DMBSeD/Al based on nanofibrous switching layers shows switching characteristics at compliance current of 10 mA with V set = 0.79 V and V reset = À 0.55 V. This work will be beneficial for the rational design of advanced next-generation organic memory devices by controlling the nanostructured morphology of active organic switching layer for enhanced charge-transfer phenomenon.[a] R.

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“…Establishment of high‐quality Schottky contacts is necessary to achieve gate modulation in heterostructure field effect transistors (HFETs). However, only a few studies have been reported on Schottky contacts to MgZnO with, for example, a barrier height of 0.73 eV, an ideality factor of 2.37, and a rectification ratio of only 10 3 . Among various Schottky metals used for ZnO, Ag has been widely adopted because of its potential to create a relatively high Schottky barrier height (1.11 eV on bulk ZnO) with an ideality factor close to unity (1.08) .…”

Section: Electron Mobilities Sheet Carrier Concentrations Schottky mentioning

confidence: 99%

Characterization of Ag Schottky Barriers on Be_0.02Mg_0.26ZnO/ZnO Heterostructures

Ullah

Ding

Nakagawara

et al. 2017

Physica Rapid Research Ltrs

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The BeMgZnO/ZnO heterostructures are capable of producing sufficiently high sheet electron densities to allow field effect transistor operation near or at the LO phonon plasmon resonance frequency for minimal LO phonon lifetimes and high electron velocity. Schottky barriers are imperative for the implementation of the aforementioned devices. Therefore, we have undertaken fabrication and characterization of Ag Schottky barriers on Zn-polar Be 0.02 Mg 0.26 ZnO/ZnO heterostructures, exhibiting the said two-dimensional electron gas (2DEG), grown by molecular beam epitaxy. Ag Schottky barriers are characterized by current-voltage (I-V) measurements in the temperature range from 80 to 400 K. At room temperature, the highest barrier height of 1.07 eV and an ideality factor of 1.22 are achieved with a rectification ratio of about eight orders of magnitude. Richardson constants of 38 AE 22 and 29 AE 20 A cm À2 K À2 are found using modified Richardson plots from Schottky diodes fabricated on two different structures. These values are consistent with the theoretical estimate of 36 A cm À2 K À2 for Be 0.02 Mg 0.26 ZnO. The temperature variation of barrier heights and ideality factors, an aberration from pure thermionic behavior, has been explained with plausible spatial inhomogeneity of barrier height with three Gaussian distributions in the temperature ranges of 80-200, 220-280, and 300-400 K.ZnO as a wide bandgap semiconductor [1] (%3.3 eV at room temperature) with high electron saturation velocity [2] (theoretical 3.5 Â 10 7 cm s À1 ), has garnered popularity owing to its potential for applications in thin film transparent transistors, transparent electrodes for solar cells, light emitters, chemical and biological sensors etc. [1,[3][4][5] Alloying with other II-VI oxides with higher bandgap (MgO and BeO) paves the way for heterojunction field effect transistors with polarization induced two-dimensional electron gas (2DEG). [6,7] Performance of such devices at high electric field, where electron transport is highly controlled by longitudinal optical (LO) phonons, [8] suffers due to accumulation of non-equilibrium hot LO phonons owing to strong electron-LO phonon coupling. Devices operating at or near plasmon-LO phonon resonance exhibit high electron drift velocity [9][10][11] allowed by ensuing ultrafast decay of hot LO phonons, [12,13] which leads to faster electron energy relaxation [14] and optimum device operation conditions (higher frequencies, lower degradation). [8] Plasmon-LO phonon resonance occurs when the energy of the LO phonon becomes similar to the plasmon energy, which occurs in ZnO at a bulk carrier concentration of %7 Â 10 18 cm À3 (ZnO LO phonon energy 72 meV). [14] Clearly, this is far beyond the MESFET operating window (typically 1 Â 10 17 À5 Â 10 17 cm À3 ). The necessity of high electron density makes the use of ZnO heterostructures with 2DEG imperative.Sheet carrier densities up to 8 Â 10 12 cm À2 (corresponding bulk concentration of 2 Â 10 19 cm À3 ) have been reported with MgZnO/ZnO heterostructu...

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Investigation of barrier inhomogeneities and interface state density in Au/MgZnO: Ga Schottky contact

Cited by 40 publications

References 73 publications

Current Transport Mechanism in Palladium Schottky Contact on Si-Based Freestanding GaN

Current Transport Mechanism in Palladium Schottky Contact on Si-Based Freestanding GaN

Benzoselenadiazole‐Based Conjugated Molecules: Active Switching Layers with Nanofibrous Morphology for Nonvolatile Organic Resistive Memory Devices

Characterization of Ag Schottky Barriers on Be_0.02Mg_0.26ZnO/ZnO Heterostructures

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Investigation of barrier inhomogeneities and interface state density in Au/MgZnO: Ga Schottky contact

Cited by 40 publications

References 73 publications

Current Transport Mechanism in Palladium Schottky Contact on Si-Based Freestanding GaN

Current Transport Mechanism in Palladium Schottky Contact on Si-Based Freestanding GaN

Benzoselenadiazole‐Based Conjugated Molecules: Active Switching Layers with Nanofibrous Morphology for Nonvolatile Organic Resistive Memory Devices

Characterization of Ag Schottky Barriers on Be0.02Mg0.26ZnO/ZnO Heterostructures

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Characterization of Ag Schottky Barriers on Be_0.02Mg_0.26ZnO/ZnO Heterostructures