Economy of New York City feet (37.2 million m) that same year, is the largest central business district in the world. New York City is distinctive for its high concentrations of advanced service sector firms in the law, accountancy, banking and management consultancy fields. It is the top global center for the advertising industry, which is metonymously called "Madison Avenue". Silicon Alley, metonymous for New York's broad-spectrum high technology sphere, continues to expand. Finance, high technology, real estate, insurance, and health care all form the basis of New York's economy. The city is also the nation's most important center for mass media, journalism, and publishing.
Polycrystalline silicon grain boundaries, see figure 1. The resistivity, mobility, and free-carrier concentration in monocrystalline silicon vary with doping concentration of the single crystal silicon. Whereas the doping of polycrystalline silicon does have an effect on the resistivity, mobility, and free-carrier concentration, these properties strongly depend on the polycrystalline grain size, which is a physical parameter that the material scientist can manipulate. Through the methods of crystallization to form polycrystalline silicon, an engineer can control the size of the polycrystalline grains which will vary the physical properties of the material. The use of polycrystalline silicon in the production of solar cells requires