Polarization Doped Nanowire Devices as an Alternative to Impurity Doping

In the past several decades, semiconductor materials have been used in a wide range of electronic devices. These devices include transistors, light emitting diodes, lasers, photodetectors, solar cells, and many more. Given such an impressive range of applications, one might wonder what makes semiconductors so different from other materials? At the heart of it, semiconductors are different from other materials because it is possible to control the electrical conductivity in semiconductors. Without this essential trait, none of the devices previously mentioned would be possible. And as semiconductor technologies have progressed, the line between semiconductors and insulators (materials that are generally not electrically conductive) has changed. That is, over time, researchers in search of new materials to meet the need of emerging applications find ways to control the conductivity in materials that were previously not conducting, thus changing an insulator to a semiconductor. However, this ability to modulate electrical conductivity using traditional methods can only go so far, and because of this limitation, new methods of controlling conductivity are desired. To explain this in greater detail, we'll first look at the method traditionally used to control conductivity, called impurity doping. Impurity doping has been the key to controlling conductivity in semiconductors for decades. This method works by adding small concentrations of foreign atoms (i.e. impurities) to an otherwise nearly perfect semiconductor crystal. The electrical conductivity of the material is modulated by changing the concentration of the atoms added. Also, the type of atoms makes a difference as well, with different atoms resulting in one of two types of conductivity, n-type or p