Читать книгу Semiconductor Basics - George Domingo - Страница 21

Perhaps the best way to summarize what we have covered in this chapter is to take a look at Figure 1.15. Observations of the sun's light spectrum and the spectra of different gases with their distinct lines resulted in heuristic relationships that relate the frequency of the missing lines to an expression consisting of just a constant and integer numbers. Einstein, working with the photoelectric effect, postulated the dual nature of light acting as both a wave and a particle, which we now call the photon.

Figure 1.15 The scientific and experimental work that led to the Bohr planetary model of the atom.

On the atomic side, Mendeleev classified the known elements by their weight, and, in the process, he left some empty spaces to add future elements. Thomson determined that electrons are tiny negatively charged particles and Rutherford, with his alpha ray measurements, concluded that the nucleus is concentrated in a very small region at the center of the atom. Millikan was able to measure the charge of electrons.

Based on previous theoretical and experimental work, Bohr proposed his planetary model of the atom with discrete and stable energy levels. His model included all the developments of atomic theory known to that date and explained the previous optical observations and measurements beautifully by considering how electrons move from one level to another by accepting or releasing packets of energy.

If you are comfortable with these conclusions, you are ready to go to the next chapter. You may peruse the three following appendices for a few more details.