Enhanced Performance of MoS<sub>2</sub> Photodetectors by Inserting an ALD‐Processed TiO<sub>2</sub> Interlayer

Pak, Yusin; Park, Woojin; Mitra, Somak; Aravindh, S. Assa; Loganathan, Kalaivanan; Kumaresan, Yogeenth; Kim, Yonghun; Cho, Byungjin; Jung, Gun‐Young; Hussain, Muhammad Mustafa; Roqan, Iman S.

doi:10.1002/smll.201703176

Cited by 52 publications

(75 citation statements)

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“…A high source–drain voltage of 10 V was required to activate a hole conducting channel due to the large channel length of 50 µm and a porous morphology of the MnO QDs layer. Under negative gate voltages, holes as the majority carriers are accumulated sufficiently enough to open the hole channel, which means that the gate voltage offsets or pushes out negative charges in the vicinity of the interface between the MnO QDs and the SiO 2 substrate …”

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confidence: 99%

“…The rise and decay time are also in the acceptable range (hundreds of milliseconds), as shown in Figure d as well as discussed in more detail in Figure S6 in the Supporting Information. However, treating the QD surface defects can improve the response time, while adopting a heterojunction structure, having optimized band alignment, can further enhance the carrier collection efficiency as well as response time …”

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confidence: 99%

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Novel P‐Type Wide Bandgap Manganese Oxide Quantum Dots Operating at Deep UV Range for Optoelectronic Devices

Mitra

Pak

Alaal

et al. 2019

Advanced Optical Materials

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in a wide range of industrial applications, such as homeland security, medical diagnostics, food curing, sanitation, chemical and biological threat detection, space-tospace communications, missile detection, military surveillance, target detection and acquisition, transparent thin-film transistors, solar cells, white lighting, sterilization, medical treatment, and touch display panels. [1][2][3][4][5][6][7] For example, the most commercial DUV photodetectors are produced using UV-enhanced narrow bandgap semiconductors, mainly Si-based photodetector. [8,9] However, the narrow bandgap materials are ineffective in rejecting signals in the UV−vis−IR spectral region, making them unsuitable for DUV applications. Thus, high-quality DUV WBGSs are still needed to produce high-performance DUV optoelectronic devices. In each of the aforementioned fields, scientists and industry practitioners are looking to overcome different challenges. There is a growing demand for both p-type and n-type WBGSs that possess good stability and conductivity. The main obstacle to the achievement of this goal stems from the lack of p-type wide bandgap materials operating in the DUV range below 300 nm (i.e., >4.1 eV) that exhibit good p-type stability. Currently, the p-type materials having bandgap in the UV-A range (such as p-type GaN, Cu 2 O, and SnO) are utilized in DUV optoelectronics, which severely downgrade device performance, as their bandgaps are limited to the UV-A-to-visible spectral region (320-400 nm). [10,11] Moreover, though n-type WBGSs (e.g., ZnO, Ga 2 O 3 , and AlGaN) with good conductivity and stability can operate in the UV and DUV range (280−390 nm), it is not possible to convert them to a p-type material with good stability and conductivity due to their intrinsic electronic properties. [2,6,[11][12][13][14][15][16] Consequently, no highly stable conductive p-type DUV WBGS operating in both UV-B and UV-C region presently exists. [17] Further advances in the field of DUV optoelectronics are hindered by other issues, such as the difficulty in developing new cost-effective material production and fabrication methods that could replace the expensive and high vacuum-based technologies presently in use. Thus, as DUV-WBGS based devices tend Wide bandgap semiconductor (WBGS)-based deep UV (DUV) devices lag behind those operating in the visible and IR range, as no stable p-type WBGS that operates in the DUV region (<300 nm) presently exists. Here, solutionprocessed p-type manganese oxide WBGS quantum dots (MnO QDs) are explored. Highly crystalline MnO QDs are synthesized via femtosecond-laser ablation in liquid. The p-type nature of these QDs is demonstrated by Kelvin probe and field effect transistor measurements, along with density functional theory calculations. As proof of concept, a high-performance, self-powered, and solar-blind Schottky DUV photodetector based on such QDs is fabricated, which is capable of detecting under ambient conditions. The carrier collection efficiency is enhanced by asymmetric electrode structure, leadi...

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confidence: 99%

Novel P‐Type Wide Bandgap Manganese Oxide Quantum Dots Operating at Deep UV Range for Optoelectronic Devices

Mitra

Pak

Alaal

et al. 2019

Advanced Optical Materials

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“…This linearity is generally hindered by defect sites, as they can severely disturb the drift of electrons and holes at low voltages. [38][39][40] At V G = 0 V, the R ph values were 3.1, 21, and 0.46 mA/W for the pristine SiO 2 PD (Figure 4a), lateral SNRs PD (Figure 4c), vertical SNRs PDs (Figure 4d), respectively. In the lateral SNRs PD, the enhancement in I ph was remarkable with a V G increment.…”

Section: Resultsmentioning

confidence: 98%

“…Overall, the R ph values of three PDs increased linearly with the V G (>0 V). This linearity is generally hindered by defect sites, as they can severely disturb the drift of electrons and holes at low voltages . At V G =0 V, the R ph values were 3.1, 21, and 0.46

μ

A/W for the pristine SiO 2 PD (Figure a), lateral SNRs PD (Figure c), vertical SNRs PDs (Figure d), respectively.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Photo‐Response of Mos₂ Photodetectors by a Laterally Aligned SiO₂ Nanoribbon Array Substrate

et al. 2019

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Achieving both high photocurrent and small dark current is required for the enhanced performance of molybdenum disulfide (MoS2) photodetector (PD). In the two‐dimensional transition metal dichalcogenide PD, inevitable recombinations occur highly at intrinsic defects of MoS2 and impede photo‐generated carrier releasement into electrodes, resulting in a poor PD performance. To address this issue without introducing a superiorly high‐crystalline MoS2 monolayer and/or complex PD architecture, we for the first time report a facile method of simply transferring the MoS2 onto a periodically aligned silicon dioxide nanoribbons (SNR) array substrate fabricated by 325 nm laser interference lithography. Interestingly, two different n‐doping states are arranged alternately on the MoS2 layer, depending on the underlying region of contact substrate (pristine SiO2 and SNR). The different n‐doping levels induce internal electric fields by which photo‐generated carriers are separated, reducing the recombination chance. The MoS2 PD on the SNR array substrate shows an improved photocurrent to dark current ratio of ∼360 (∼7 times larger than that of the reference PD on the pristine SiO2 substrate), while producing a small dark current of ∼10−12 A at VG=0 V. Our method paves the way for enhancing the performance of other 2D materials‐based optoelectronic devices.

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“…Recently, as the popularity of TMDs has grown up, new tactics have been continuously developed. Mostly, lateral and vertical heterojunctions formed by TMDs and other 2DMs have been regarded as a promising way to obtain novel devices . Thus far, graphene/MoS 2 ‐ or /WS 2 ‐ or WSe 2 ‐based photodetectors have been reported .…”

Section: Optoelectronic Devicesmentioning

confidence: 99%

2D Transition Metal Dichalcogenide Thin Films Obtained by Chemical Gas Phase Deposition Techniques

Park

Nielsch

Thomas

2018

Adv Materials Inter

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Ultrathin 2D transition metal dichalcogenide (TMD) thin films have attracted much attention due to their very good electrical, optical, and electrochemical properties. Chemical vapor deposition (CVD) and atomic layer deposition (ALD), which is in some regards an enhanced version of CVD, are techniques that can provide exceptionally conformal large‐area coatings, even for complex surface geometries. Besides, these techniques include the transport of one or more precursor chemicals in the gas phase onto a substrate. Subsequently, a chemical reaction occurs, resulting in the deposition of a film of a solid material on the substrate. One of the advantageous aspects of chemical deposition methods, such as CVD and ALD, is the growth of thin films onto a variety of substrates as well as 3D structures. Because of their chemical approach, these techniques are well suited to synthesizing 2D materials (2DMs) with a low defect concentration. Furthermore, the scalability would allow industrial application, as opposed to, e.g., micromechanical cleavage. Here, the recent progress in 2D TMD thin films is reviewed and the current applications of these materials fabricated by CVD and ALD are surveyed.

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Enhanced Performance of MoS₂ Photodetectors by Inserting an ALD‐Processed TiO₂ Interlayer

Cited by 52 publications

References 31 publications

Novel P‐Type Wide Bandgap Manganese Oxide Quantum Dots Operating at Deep UV Range for Optoelectronic Devices

Novel P‐Type Wide Bandgap Manganese Oxide Quantum Dots Operating at Deep UV Range for Optoelectronic Devices

Enhanced Photo‐Response of Mos₂ Photodetectors by a Laterally Aligned SiO₂ Nanoribbon Array Substrate

2D Transition Metal Dichalcogenide Thin Films Obtained by Chemical Gas Phase Deposition Techniques

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Enhanced Performance of MoS2 Photodetectors by Inserting an ALD‐Processed TiO2 Interlayer

Cited by 52 publications

References 31 publications

Novel P‐Type Wide Bandgap Manganese Oxide Quantum Dots Operating at Deep UV Range for Optoelectronic Devices

Novel P‐Type Wide Bandgap Manganese Oxide Quantum Dots Operating at Deep UV Range for Optoelectronic Devices

Enhanced Photo‐Response of Mos2 Photodetectors by a Laterally Aligned SiO2 Nanoribbon Array Substrate

2D Transition Metal Dichalcogenide Thin Films Obtained by Chemical Gas Phase Deposition Techniques

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Enhanced Performance of MoS₂ Photodetectors by Inserting an ALD‐Processed TiO₂ Interlayer

Enhanced Photo‐Response of Mos₂ Photodetectors by a Laterally Aligned SiO₂ Nanoribbon Array Substrate