In order to get a general idea of the properties of material objects and the laws according to which "lives" familiar to everyone macrocosm, not necessarily to finish university, because every day is faced with its manifestations.Although in recent years have increasingly referred to the principle of similarity, which supporters argue that the micro and macrocosm are very similar, however, the difference is still there.This is especially noticeable in the very small size of bodies and objects.Quantum dots, sometimes called nanodots, just represent one of these cases.
Less smaller
Let us recall the classical device atoms, such as hydrogen.It includes a core, which due to the presence therein of a positively charged proton has a plus-electric charge, i.e. +1 (since hydrogen - the first element in the periodic table).Accordingly, at a certain distance from the core is electron (-1) to form an electron shell.Obviously, if you increase the value of the nuclear charge, it would entail the incorporation of new electrons (remember: the whole atom is electrically neutral).
distance between each electron and the nucleus is determined by energy levels of negatively charged particles.Each orbit is constant, the total configuration of the particles determines the material.Electrons can jump from one orbit to another by absorbing or releasing energy by photons of a particular frequency.At the outermost orbits are electrons with a maximum energy level.Interestingly, he shows the dual nature of a photon, to determine both a massless particle and electromagnetic radiation.
terms
word "photon" of Greek origin, it means "a particle of light."Therefore, it can be argued that the change of the electron in its orbit, it absorbs (highlights) the quantum of light.In this case it is appropriate to explain the meaning of another word - "quantum".In fact, nothing complicated.The word comes from the Latin «quantum», which literally translates as the lowest value of any physical quantity (here - radiation).Here is an example that this quantum: if the measurement of the weight of the smallest indivisible quantity is milligrams, it could be called.That's easy to explain seemingly complex term.
Quantum dots: explanation
often in textbooks can be found the following definition for the nanodots - this is an extremely small particle of any material of a size comparable to the magnitude of the emitted wavelength of the electron (the full range of covers ranging from 1 to 10 nanometers).Inside it the potential energy of a single medium a negative charge is smaller than the outside, so the electron limited movements.
However, the term "quantum dots" can be explained otherwise.An electron has absorbed a photon, "rises" to a higher energy level, and in its place the image of "loss" - the so-called hole.Accordingly, if the electron has a charge of -1, then one hole.In an effort to return to the previous stable state, the electron emits a photon.Communications of carriers "-" and "+" in this case is called an exciton in physics is understood as a particle.Its size depends on the level of absorbed energy (higher orbit).Quantum dots are precisely these particles.The frequency of the emitted electron energy depends directly on the particle size of the material and exciton.It should be noted that the basis of color perception by the human eye the light is different photon energy.Each color has a certain frequency of electromagnetic radiation.
