Wafer-scale controlled growth of MoS2by magnetron sputtering: from in-plane to inter-connected vertically-aligned flakes.

Recently, Molybdenum disulfide (MoS2) has attracted great attention due to its unique characteristics and potential applications in various fields. The advancements in the field have substantially improved at the laboratory scale however, a synthesis approach that produces large area growth of MoS2on a wafer scale is the key requirement for the realization of commercial two-dimensional (2D) technology. Herein, we report tunable MoS2growth with varied morphologies via radio frequency magnetron sputtering by controlling growth parameters. The controlled growth from in-plane to vertically-aligned (VA) MoS2flakes has been achieved on a variety of substrates (Si, Si/SiO2, sapphire, quartz, and carbon fiber). Moreover, the growth of VA MoS2is highly reproducible and is fabricated on a wafer scale. The flakes synthesized on the wafer show high uniformity, which is corroborated by the spatial mapping using Raman over the entire 2-inch Si/SiO2wafer. The detailed morphological, structural, and spectroscopic analysis reveals the transition from in-plane MoS2to VA MoS2flakes. This work presents a facile approach to directly synthesize layered materials by sputtering technique on wafer scale. This paves the way for designing mass production of high-quality 2D materials, which will advance their practical applications by integration into device architectures in various fields.

Platinum nanoparticle sensitized plasmonic-enhanced broad spectral photodetection in large area vertical-aligned MoS2flakes.

2D MoS2holds immense potential for electronic and optoelectronic applications due to its unique characteristics. However, the atomic-scale thickness of MoS2hinders the optical absorbance, thereby limiting its photodetection capability. Vertically-aligned MoS2(VA-MoS2) has an advantage of strong optical absorption and quick intra-layer transport, offering high speed operation. The coupling of plasmonic metal nanostructure with MoS2can further enhance the light-matter interaction. Pt/Pd (as opposed to Ag/Au) are more promising to design next-generation nano-plasmonic devices due to their intense interband activity over a broad spectral range. Herein, we report Pt nanoparticle (NPs) enhanced broadband photoresponse in VA-MoS2. The optical absorbance of MoS2is enhanced after the integration of Pt NPs, with a four-fold enhancement in photocurrent. The formation of Schottky junction at Pt-MoS2interface inhibits electron transmission, suppressing the dark current and substantially reducing NEP. The plasmonic-enabled photodetector shows enhanced responsivity (432 A W-1, 800 nm) and detectivity (1.85 × 1014Jones, 5 V) with a low response time (87 ms/84 ms), attributed to faster carrier transport. Additionally, a theoretical approach is adopted to calculate wavelength-dependent responsivity, which matches well with experimental results. These findings offer a facile approach to modulate the performance of next-generation optoelectronic devices for practical applications.

White matter hyperintensities in young individuals with bipolar disorder or at high genetic risk.

BACKGROUND: Increased white matter hyperintensities (WMHs) is one of the most consistent imaging findings amongst participants with bipolar disorder (BD). This study investigated WMHs in a young population at high genetic risk for bipolar disorder (HR). METHODS: MRI scans were conducted at baseline in HR individuals (n = 131), patients with BD (n = 47) and controls (CON) (n = 108). Most of the HR (n = 77) and CON (n = 74) group completed scans after two years. Scans were examined for the presence of WMHs. RESULTS: There were significantly more periventricular WMHs in the BD compared to the CON group at baseline (p = .04). Although the prevalence of periventricular WMHs was intermediate in the HR group, there were no significant differences between the HR and CON or BD participants. Deep WMHs did not differ significantly between the groups. Over time, there was a significant increase in the prevalence of periventricular WMHs in both the HR and CON groups (p = .02). LIMITATIONS: The use of a visual rating scale to examine WMHs is subjective. As the gradings were collapsed into 'present' or 'absent', we could not ascertain whether the severity of hyperintensities worsened over time. CONCLUSIONS: Periventricular WMHs are more prevalent in young individuals with BD than controls. As these are not more prevalent in HR individuals, it is possible that these are either secondary to the development of bipolar disorder, its treatment, or resulting changes in lifestyle. In a novel finding, there were similar increases in the prevalence of WMHs in controls and HR youth over the 2-year period.