Martin Klima

Bio: Martin Klima is an academic researcher from Columbia University. The author has contributed to research in topics: Graphene & Graphene foam. The author has an hindex of 3, co-authored 4 publications receiving 6775 citations.

Observation of Graphene Bubbles and Effective Mass Transport under Graphene Films

Abstract: Mechanically exfoliated graphene mounted on a SiO2/Si substrate was subjected to HF/H(2)O etching or irradiation by energetic protons. In both cases gas was released from the SiO2 and accumulated at the graphene/SiO2 interface resulting in the formation of "bubbles" in the graphene sheet. Formation of these "bubbles" demonstrates the robust nature of single layer graphene membranes, which are capable of containing mesoscopic volumes of gas. In addition, effective mass transport at the graphene/SiO2 interface has been observed.

Methods for graphene-assisted fabrication of micro-and nanoscale structures and devices featuring the same

Abstract: Methods for graphene-assisted fabrication of a surface on a substrate are disclosed herein. In an exemplary method, fabricating an etched surface on a substrate includes, depositing at least one layer of graphene on the surface on the substrate, patterning the deposited layer of graphene, and exposing the surface on a substrate to an acid to etch the surface on the substrate. The method can further include forming the layer of graphene from graphite. In some embodiments, the layer of graphene is formed by mechanically exfoliating the layer of graphene from the graphite. Alternatively, the layer of graphene can be formed by chemically exfoliating the graphene from the graphite, or other carbon materials, and/or utilizing vapor deposition to form the layer of graphene from the graphite, or other carbon materials.

Self-organization phenomena in cold atmospheric pressure plasma slit jet

Abstract: The radio frequency plasma slit jet, which produces 150 mm wide streaming plasma outside the jet body, exhibits exciting self-organization phenomena that resemble the self-organized patterns of dielectric barrier discharge (DBD) filaments. Similarly, as in DBD, the filaments are surrounded by an inhibition zone that does not allow two filaments to come closer to each other. With fast camera imaging, we observed the filamentary character of the discharge in all the studied gas feeds (Ar, Ar/N2, and Ar/O2). Still, the visual appearance of the filaments in the plasma and their interaction with a dielectric surface depended significantly on the gas feed. As the breakdown voltage in pure Ar is relatively low compared to the applied one, new filaments form frequently. Such newly created filaments disrupted the characteristic inter-filament distance, forcing the system to rearrange. The frequent ignition and decay processes in Ar led to short filament lifetimes (0.020–0.035 s) and their high jitter speed (0.9–1.7 m s−1), as determined with an image processing custom code based on Gwyddion libraries. The number of filaments was lower in the Ar/O2 and Ar/N2 mixtures. It was attributed to a loss of energy in the excitation of rotational and vibrational levels and oxygen electronegativity. Since the probability of low-current side discharges transitioning into the full plasma filaments was limited in these gas mixtures, the self-organized pattern was seldom disrupted, leading to lesser movement and longer lifetimes. Unlike in Ar or Ar/O2, the constricted filaments in Ar/N2 were surrounded by diffuse plasma plumes, likely connected to the presence of long-lived nitrogen species. We demonstrated in the polypropylene treatment that the self-organization phenomena affected the treatment uniformity.

Procédé de fabrication assistée au graphène de structures microscopiques et nanoscopiques et dispositifs les comportant

Abstract: La presente invention concerne des procedes de fabrication assistee au graphene d’une surface sur un substrat. Dans un procede d’exemple, la fabrication d’une surface gravee sur un substrat consiste a deposer au moins une couche de graphene sur la surface du substrat, a tracer des motifs sur la couche de graphene deposee, et a exposer la surface sur un substrat a un acide pour graver la surface sur le substrat. Le procede peut en outre consister a former la couche de graphene a partir de graphite. Dans certains modes de realisation, la couche de graphene est formee par exfoliation mecanique de la couche de graphene a partir du graphite. En variante, la couche de graphene peut etre formee par exfoliation chimique du graphene a partir du graphite, ou d’autres materiaux au carbone, et/ou a utiliser le depot en phase vapeur pour former la couche de graphene a partir du graphite ou d’autres materiaux au carbone.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Single-layer MoS2 transistors

Abstract: Two-dimensional materials are attractive for use in next-generation nanoelectronic devices because, compared to one-dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two-dimensional material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS(2) have a large intrinsic bandgap of 1.8 eV (ref. 16), previously reported mobilities in the 0.5-3 cm(2) V(-1) s(-1) range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room-temperature single-layer MoS(2) mobility of at least 200 cm(2) V(-1) s(-1), similar to that of graphene nanoribbons, and demonstrate transistors with room-temperature current on/off ratios of 1 × 10(8) and ultralow standby power dissipation. Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS(2) could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.

Large-scale pattern growth of graphene films for stretchable transparent electrodes

Abstract: Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.

Graphene and Graphene Oxide: Synthesis, Properties, and Applications

Abstract: There is intense interest in graphene in fields such as physics, chemistry, and materials science, among others. Interest in graphene's exceptional physical properties, chemical tunability, and potential for applications has generated thousands of publications and an accelerating pace of research, making review of such research timely. Here is an overview of the synthesis, properties, and applications of graphene and related materials (primarily, graphite oxide and its colloidal suspensions and materials made from them), from a materials science perspective.