Germanium is a group 4A semiconductor. The addition of a dopant atom (group 3A element) that has fewer valence electrons than th
e host atom results in a p-type semiconductor. The addition of a dopant atom (group 5A elements) that has more valence electrons than the host atom results in an n-type semiconductor. Which of the following elements when used for doping germanium will yield p-type semiconductors, and which elements when used for doping germanium will yield n-type semiconductors?
Doping with galium or indium will yield a p-type semiconductor while doping with arsenic, antimony or phosphorus will yield an n-type semiconductor.
Explanation:
Doping refers to improving the conductivity of a semiconductor by addition of impurities. A trivalent impurity leads to p-type semiconductor while a pentavalent impurity leads to an n-type semiconductor.
The conservation of energy principle states that energy can neither be destroyed nor created. Instead, energy just transforms from one form into another. So what exactly is energy transformation? Well, as you might guess, energy transformation is defined as the process of changing energy from one form to another. There are so many different kinds of energy that can transform from one form to another. There is energy from chemical reactions called chemical energy, energy from thermal processes called heat energy, and energy from charged particles called electrical energy. The processes of fission, which is splitting atoms, and fusion, which is combining atoms, give us another type of energy called nuclear energy. And finally, the energy of motion, kinetic energy, and the energy associated with position, potential energy, are collectively called mechanical energy. That sounds like quite a lot, doesn't it? Well it is, but don't worry, it's actually all pretty easy to remember. Next, we'll explore all of these kinds of possible transformations in more detail. Different Types of Energy Transformations Chemical energy is the energy stored within a substance through the bonds of chemical compounds. The energy stored in these chemical bonds can be released and transformed during any type of chemical reaction. Think of when you're hungry. When you eat a piece of bread to satisfy this hunger, your body breaks down the chemical bonds of the bread and uses it to supply energy to your body. In this process, the chemical energy is transformed into mechanical energy, which you use to move, and which we'll cover in more detail in a moment. It also transforms it into thermal energy, which is created through the metabolic processes in your body to generate heat. Most of the time, chemical energy is released in the form of heat, and this transformation from chemical energy to heat, or thermal energy, is called an exothermic reaction. Next, there are two main types of mechanical energy: kinetic energy and potential energy. Kinetic energy is the energy associated with the motion of an object. Therefore, any object that moves has kinetic energy. Likewise, there are two types of potential energy: gravitational potential energy and elastic potential energy. Gravitational potential energy is associated with the energy stored by an object because of its location above the ground. Elastic potential energy is the energy stored by any object that can stretch or compress. Potential energy can be converted to kinetic energy and vice versa. For example, when you do a death-defying bungee jump off of a bridge, you are executing a variety of energy transformations. First, as you prepare to jump, you have gravitational potential energy - the bungee cord is slack so there is no elastic potential energy. Once you jump, you convert this gravitational potential energy into kinetic energy as you fall down. At the same time, the bungee cord begins to stretch out. As the cord stretches, it begins to store elastic potential energy. You stop at the very bottom when the cord is fully stretched out, so at this point, you have elastic potential energy. The cord then whips you back up, thereby converting the stored elastic potential energy into kinetic energy and gravitational potential energy. The process then repeats
The superscript of indicates that each of these ions carries a charge of . That corresponds to the shortage of one electron for each ion.
Similarly, the superscript on each ion indicates a shortage of three electrons per such ion.
Assume that the coefficient of (among the reactants) is , and that the coefficient of (among the reactants) is .
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There would thus be silver () atoms and aluminum () atoms on either side of the equation. Hence, the coefficient for and would be and , respectively.
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The ions on the left-hand side of the equation would correspond to the shortage of electrons. On the other hand, the ions on the right-hand side of this equation would correspond to the shortage of electrons.
Just like atoms, electrons are also conserved in a chemical reaction. Therefore, if the left-hand side has a shortage of electrons, the right-hand side should also be electrons short of being neutral. On the other hand, it is already shown that the right-hand side would have a shortage of electrons. These two expressions should have the same value. Therefore, .
The smallest integer and that could satisfy this relation are and . The equation becomes: