Candidates for Aristotle\u27s Natural Slaves

The aim of this paper is to identify empirically potential candidates for natural slaves among the vast number of coerced workers in the ancient world, barbarian and Greek alike

Note on the 3-graph counting lemma

AbstractSzemerédi's regularity lemma proved to be a powerful tool in extremal graph theory. Many of its applications are based on the so-called counting lemma: if G is a k-partite graph with k-partition V1∪⋯∪Vk, |V1|=⋯=|Vk|=n, where all induced bipartite graphs G[Vi,Vj] are (d,ε)-regular, then the number of k-cliques Kk in G is dk2nk(1±o(1)). Frankl and Rödl extended Szemerédi's regularity lemma to 3-graphs and Nagle and Rödl established an accompanying 3-graph counting lemma analogous to the graph counting lemma above. In this paper, we provide a new proof of the 3-graph counting lemma

An Extremal Problem for Finite Lattices

For a fixed M x N integer lattice L(M,N), we consider the maximum size of a subset A of L(M,N) which contains no squares of prescribed side lengths k(1),...,k(t). We denote this size by ex(L(M,N), {k(1),...,k(t)}), and when t = 1, we abbreviate this parameter to ex(L(M,N), k), where k = k(1). Our first result gives an exact formula for ex(L(M,N), k) for all positive integers k, M, and N, where ex(L(M,N), k) = ((3/4) + o(1)) MN holds for fixed k and diverging M and N. Our second result identifies a subset A0 of L(M,N) of size at least (2/3)MN with the property that, for any integer k not divisible by three, A0 contains no squares of side length k. Our third result shows that |A0| is asymptotically best possible, in that for all positive integers M and N, we have ex(L(M,N), {1,2}) \u3c (2/3)MN + O(M+N). When M = 3m, our estimates on the error above render exact formulas for ex(L(3m,3), {1,2}) and ex(L(3m,6), {1,2})

Back-gated Nb-doped MoS2 junctionless field-effect-transistors

Electrical measurements were carried out to measure the performance and evaluate the characteristics of MoS2 flakes doped with Niobium (Nb). The flakes were obtained by mechanical exfoliation and transferred onto 85 nm thick SiO2 oxide and a highly doped Si handle wafer. Ti/Au (5/45 nm) deposited on top of the flake allowed the realization of a back-gate structure, which was analyzed structurally through Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). To best of our knowledge this is the first cross-sectional TEM study of exfoliated Nb-doped MoS2 flakes. In fact to date TEM of transition-metal-dichalcogenide flakes is extremely rare in the literature, considering the recent body of work. The devices were then electrically characterized by temperature dependent Ids versus Vds and Ids versus Vbg curves. The temperature dependency of the device shows a semiconductor behavior and, the doping effect by Nb atoms introduces acceptors in the structure, with a p-type concentration 4.3 × 1019 cm−3 measured by Hall effect. The p-type doping is confirmed by all the electrical measurements, making the structure a junctionless transistor. In addition, other parameters regarding the contact resistance between the top metal and MoS2 are extracted thanks to a simple Transfer Length Method (TLM) structure, showing a promising contact resistivity of 1.05 × 10−7 Ω/cm2 and a sheet resistance of 2.36 × 102 Ω/sq

3D interconnection by FIB assisted Pt deposition and electroless nickel deposition on the sides and edges of an I-Seed

This paper reports on the development of a 3D interconnection process leading to the successful assembly of a five-layer 3-D 1mm cube module. This proof of concept module demonstrates the capability for successful integration and interconnection of commercial off the shelf components to fabricate functional modules in 1mm cube dimensions. It also demonstrates that use of established volume scale technologies like Flip-chip, dicing and patterning techniques are viable for fabricating these 1mm modules. The demonstrator consists of LED's bonded to the six sides of the 1mm cube, interconnected and powered up. The work will particularly report on two different processes to fabricate the interconnection pattern using direct Focused Ion Beam (FIB) assisted Pt deposition and electroless metal deposition, which again patterned by FIB. Uniform thickness of the deposit and excellent coverage on all six sides is achieved by electroless nickel deposition. Voltage current characterisation of the deposited Pt shows a resistivity value of 1864 +/- 100 mu Omega cm, whereas electroless Ni film shows a resistivity of 25 mu Omega cm due to boron inclusion. 100 nm An layer is deposited by chemical displacement reaction to enhance the conductivity and solderability of the film

Back-gated Nb-doped MoS2 junctionless field-effect-transistors

Electrical measurements were carried out to measure the performance and evaluate the characteristics of MoS2 flakes doped with Niobium (Nb). The flakes were obtained by mechanical exfoliation and transferred onto 85 nm thick SiO2 oxide and a highly doped Si handle wafer. Ti/Au (5/45 nm) deposited on top of the flake allowed the realization of a back-gate structure, which was analyzed structurally through Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). To best of our knowledge this is the first cross-sectional TEM study of exfoliated Nb-doped MoS2 flakes. In fact to date TEM of transition-metal-dichalcogenide flakes is extremely rare in the literature, considering the recent body of work. The devices were then electrically characterized by temperature dependent Ids versus Vds and Ids versus Vbg curves. The temperature dependency of the device shows a semiconductor behavior and, the doping effect by Nb atoms introduces acceptors in the structure, with a p-type concentration 4.3 × 1019 cm−3 measured by Hall effect. The p-type doping is confirmed by all the electrical measurements, making the structure a junctionless transistor. In addition, other parameters regarding the contact resistance between the top metal and MoS2 are extracted thanks to a simple Transfer Length Method (TLM) structure, showing a promising contact resistivity of 1.05 × 10−7 Ω/cm2 and a sheet resistance of 2.36 × 102 Ω/sq

Structural and electronic properties of polycrystalline InAs thin films deposited on silicon dioxide and glass at temperatures below 500 °c

Polycrystalline indium arsenide (poly InAs) thin films grown at 475 °C by metal organic vapor phase epitaxy (MOVPE) are explored as possible candidates for low-temperature-grown semiconducting materials. Structural and transport properties of the films are reported, with electron mobilities of ~100 cm2/V·s achieved at room temperature, and values reaching 155 cm2/V·s for a heterostructure including the polycrystalline InAs film. Test structures fabricated with an aluminum oxide (Al2O3) top-gate dielectric show that transistor-type behavior is possible when poly InAs films are implemented as the channel material, with maximum ION/IOFF > 250 achieved at −50 °C and ION/IOFF = 90 at room temperature. Factors limiting the ION/IOFF ratio are investigated and recommendations are made for future implementation of this material