scholarly journals Synthesis of few-layer 2H-MoSe2 thin films with wafer-level homogeneity for high-performance photodetector

Nanophotonics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 1959-1969 ◽  
Author(s):  
Tian-Jun Dai ◽  
Yu-Chen Liu ◽  
Xu-Dong Fan ◽  
Xing-Zhao Liu ◽  
Dan Xie ◽  
...  
Keyword(s):  
Thin Films ◽  
High Performance ◽  
Deep Understanding ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Fast Response ◽  
Wafer Level ◽  
Large Area ◽  
Carrier Recombination ◽  
Layer Deposition

AbstractThe unique structural and physical properties of two-dimensional (2D) atomic layer semiconductors render them promising candidates for electronic or optoelectronic devices. However, the lack of efficient and stable approaches to synthesize large-area thin films with excellent uniformity hinders their realistic applications. In this work, we reported a method involving atomic layer deposition and a chemical vapor deposition chamber to produce few-layer 2H-MoSe2 thin films with wafer-level uniformity. The reduction of MoO3 was found indispensable for the successful synthesis of MoSe2 films due to the low vaporization temperature. Moreover, a metal-semiconductor-metal photodetector (PD) was fabricated and investigated systematically. We extracted an ultrahigh photoresponsivity approaching 101 A/W with concomitantly high external quantum efficiency up to 19,668% due to the produced gain arising from the holes trapped at the metal/MoSe2 interface, the band tail state contribution, and the photogating effect. A fast response time of 22 ms was observed and attributed to effective nonequilibrium carrier recombination. Additionally, the ultrahigh photoresponsivity and low dark current that originated from Schottky barrier resulted in a record-high specific detectivity of up to 2×1013 Jones for 2D MoSe2/MoS2 PDs. Our findings revealed a pathway for the development of high-performance PDs based on 2D MoSe2 that are inexpensive, large area, and suitable for mass production and contribute to a deep understanding of the photoconductivity mechanisms in atomically thin MoSe2. We anticipate that these results are generalizable to other layer semiconductors as well.

Depositing High-Performance Conductive Thin Films by Using Atomic Layer Deposition

2015 ◽  
Vol 764-765 ◽  
pp. 138-142 ◽  
Author(s):  
Fa Ta Tsai ◽  
Hsi Ting Hou ◽  
Ching Kong Chao ◽  
Rwei Ching Chang
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
High Performance ◽  
Atomic Layer ◽  
Electric Properties ◽  
X Ray Diffraction ◽  
Layer Deposition ◽  
Azo Thin Film ◽  
Aluminum Doped Zinc Oxide ◽  
Conductive Thin Films

This work characterizes the mechanical and opto-electric properties of Aluminum-doped zinc oxide (AZO) thin films deposited by atomic layer deposition (ALD), where various depositing temperature, 100, 125, 150, 175, and 200 °C are considered. The transmittance, microstructure, electric resistivity, adhesion, hardness, and Young’s modulus of the deposited thin films are tested by using spectrophotometer, X-ray diffraction, Hall effect analyzer, micro scratch, and nanoindentation, respectively. The results show that the AZO thin film deposited at 200 °C behaves the best electric properties, where its resistance, Carrier Concentration and mobility reach 4.3×10-4 Ωcm, 2.4×1020 cm-3, and 60.4 cm2V-1s-1, respectively. Furthermore, microstructure of the AZO films deposited by ALD is much better than those deposited by sputtering.

scholarly journals Nanoindentation of Chromium Oxide Possessing Superior Hardness among Atomic-Layer-Deposited Oxides

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 82
Author(s):  
Taivo Jõgiaas ◽  
Aivar Tarre ◽  
Hugo Mändar ◽  
Jekaterina Kozlova ◽  
Aile Tamm
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Organic Chemical ◽  
X Ray ◽  
Layer Deposition ◽  
Ammonium Dichromate ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Deposition Substrate

Chromium (III) oxide is a technologically interesting material with attractive chemical, catalytic, magnetic and mechanical properties. It can be produced by different chemical and physical methods, for instance, by metal–organic chemical vapor deposition, thermal decomposition of chromium nitrate Cr(NO3)3 or ammonium dichromate (NH4)2Cr2O7, magnetron sputtering and atomic layer deposition. The latter method was used in the current work to deposit Cr2O3 thin films with thicknesses from 28 to 400 nm at deposition temperatures from 330 to 465 °C. The phase composition, crystallite size, hardness and modulus of elasticity were measured. The deposited Cr2O3 thin films had different structures from X-ray amorphous to crystalline α-Cr2O3 (eskolaite) structures. The averaged hardness of the films on SiO2 glass substrate varied from 12 to 22 GPa and the moduli were in the range of 76–180 GPa, as determined by nanoindentation. Lower values included some influence from a softer deposition substrate. The results indicate that Cr2O3 could be a promising material as a mechanically protective thin film applicable, for instance, in micro-electromechanical devices.

scholarly journals Active IrO2 and NiO Thin Films Prepared by Atomic Layer Deposition for Oxygen Evolution Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 92 ◽  
Author(s):  
DJ Donn Matienzo ◽  
Daniel Settipani ◽  
Emanuele Instuli ◽  
Tanja Kallio
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Atomic Layer Deposition ◽  
Chemical Vapor ◽  
Water Electrolysis ◽  
Atomic Layer ◽  
Alkaline Water Electrolysis ◽  
Catalytic Systems ◽  
Alkaline Water ◽  
Layer Deposition

Atomic layer deposition (ALD) is a special type of chemical vapor deposition (CVD) technique that can grow uniformed thin films on a substrate through alternate self-limiting surface reactions. Recently, the application of these thin film materials to catalytic systems has begun to attract much attention, and the capacity to deposit these catalytic films in a highly controlled manner continues to gain importance. In this study, IrO2 and NiO thin films (approximately 25 to 60 nm) were deposited on industrial Ni expanded mesh as an anode for alkaline water electrolysis. Different ALD operating parameters such as the total number of deposition cycles, sublimation and deposition temperatures, and precursors pulse and purge lengths were varied to determine their effects on the structure and the electrochemical performance of the thin film materials. Results from the electrochemical tests (6 M KOH, 80 °C, up to 10 kA/m2) showed the catalytic activity of the samples. Oxygen overpotential values (ηO2) were 20 to 60 mV lower than the bare Ni expanded mesh. In summary, the study has demonstrated the feasibility of using the ALD technique to deposit uniformed and electroactive thin films on industrial metallic substrates as anodes for alkaline water electrolysis.

scholarly journals High-performance monolayer MoS2 photodetector enabled by oxide stress liner using scalable chemical vapor growth method

Nanophotonics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1981-1991 ◽  
Author(s):  
Zhiwen Li ◽  
Jing Wu ◽  
Cong Wang ◽  
Han Zhang ◽  
Wenjie Yu ◽  
...  
Keyword(s):  
High Performance ◽  
Large Scale ◽  
Surface Defects ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Light Illumination ◽  
Vapor Growth ◽  
Layer Deposition ◽  
Growth Method

AbstractMoS2, as a typical representative of two-dimensional semiconductors, has been explored extensively in applications of optoelectronic devices because of its adjustable bandgap. However, to date, the performance of the fabricated photodetectors has been very sensitive to the surrounding environment owing to the large surface-to-volume ratio. In this work, we report on large-scale, high-performance monolayer MoS2 photodetectors covered with a 3-nm Al2O3 layer grown by atomic layer deposition. In comparison with the device without the Al2O3 stress liner, both the photocurrent and responsivity are improved by over 10 times under 460-nm light illumination, which is due to the tensile strain induced by the Al2O3 layer. Further characterization demonstrated state-of-the-art performance of the device with a responsivity of 16.103 A W−1, gain of 191.80, NEP of 7.96 × 10−15 W Hz−1/2, and detectivity of 2.73 × 1010 Jones. Meanwhile, the response rise time of the photodetector also reduced greatly because of the increased electron mobility and reduced surface defects due to the Al2O3 stress liner. Our results demonstrate the potential application of large-scale strained monolayer MoS2 photodetectors in next-generation imaging systems.

Atomic Layer Deposition of Solid Lubricant Thin Films

2005 ◽  
Author(s):  
T. W. Scharf ◽  
S. V. Prasad ◽  
M. T. Dugger ◽  
T. M. Mayer
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Transition Metal ◽  
Atomic Layer Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Aspect Ratios ◽  
Layer Deposition ◽  
Vapor Deposition Technique

Tungsten disulphide (WS2) and molybdenum disulfide (MoS2), which belong to the family of transition metal dichalcogenides, are well known for their solid lubricating behavior. Thin films of MoS2 and WS2 exhibit extremely low coefficient of friction (COF ∼0.02 to 0.05) in dry environments, and are typically applied by sputter deposition, pulsed laser ablation, evaporation or chemical vapor deposition, which are essentially either line-of-sight or high temperature processes. With these techniques it is difficult to coat surfaces shadowed from the target, or uniformly coat sidewalls of three-dimensional or high aspect ratio structures. For applications such as micromechanical (MEMS) devices, where dimensions and separation tolerances are small, and aspect ratios are large, these traditional deposition techniques are inadequate. Atomic layer deposition (ALD) is a chemical vapor deposition technique that could overcome many of these problems by using sequential introduction of gaseous precursors and selective surface chemistry to achieve controlled growth at lower temperatures, but the chemistry needed to grow transition metal dichalcogenide films by ALD is not known.

scholarly journals Progresses in Synthesis and Application of SiC Films: From CVD to ALD and from MEMS to NEMS

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 799 ◽  
Author(s):  
Mariana Fraga ◽  
Rodrigo Pessoa
Keyword(s):  
Low Temperature ◽  
Low Cost ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Nanoelectromechanical Systems ◽  
Large Area ◽  
Scientific Publications ◽  
Continuous Growth ◽  
Layer Deposition ◽  
Sic Films

A search of the recent literature reveals that there is a continuous growth of scientific publications on the development of chemical vapor deposition (CVD) processes for silicon carbide (SiC) films and their promising applications in micro- and nanoelectromechanical systems (MEMS/NEMS) devices. In recent years, considerable effort has been devoted to deposit high-quality SiC films on large areas enabling the low-cost fabrication methods of MEMS/NEMS sensors. The relatively high temperatures involved in CVD SiC growth are a drawback and studies have been made to develop low-temperature CVD processes. In this respect, atomic layer deposition (ALD), a modified CVD process promising for nanotechnology fabrication techniques, has attracted attention due to the deposition of thin films at low temperatures and additional benefits, such as excellent uniformity, conformability, good reproducibility, large area, and batch capability. This review article focuses on the recent advances in the strategies for the CVD of SiC films, with a special emphasis on low-temperature processes, as well as ALD. In addition, we summarize the applications of CVD SiC films in MEMS/NEMS devices and prospects for advancement of the CVD SiC technology.

Controlled exposure of CuO thin films through corrosion-protecting, ALD-deposited TiO2 overlayers

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hamed Mehrabi ◽  
Caroline G. Eddy ◽  
Thomas I. Hollis ◽  
Jalyn N. Vance ◽  
Robert H. Coridan
Keyword(s):  
Thin Films ◽  
Energy Conversion ◽  
High Performance ◽  
Atomic Layer ◽  
Energy Conversion Efficiency ◽  
Parallel Optimization ◽  
Transfer Resistance ◽  
Thin Film Coatings ◽  
Layer Deposition ◽  
Protection Layer

Abstract Ultra-thin film coatings are used to protect semiconductor photoelectrodes from the harsh chemical environments common to photoelectrochemical energy conversion. These layers add contact transfer resistance to the interface that can result in a reduction of photoelectrochemical energy conversion efficiency of the photoelectrode. Here, we describe the concept of a partial protection layer, which allows for direct chemical access to a small fraction of the semiconductor underlayer for further functionalization by an electrocatalyst. The rest of the interface remains protected by a stable, inert protection layer. CuO is used as a model system for this scheme. Atomic layer deposition (ALD)-prepared TiO2 layers on CuO thin films prepared from electrodeposited Cu2O allow for the control of interfacial morphology to intentionally expose the CuO underlayer. The ALD-TiO2 overlayer shrinks during crystallization, while Cu2O in the underlayer expands during oxidation. As a result, the TiO2 protection layer cracks to expose the oxidized underlying CuO layer, which can be controlled by preceding thermal oxidation. This work demonstrates a potentially promising strategy for the parallel optimization of photoelectrochemical interfaces for chemical stability and high performance.

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