<Dd> Heterojunctions occur when two differently doped semiconducting materials are joined together . For example, a configuration could consist of p - doped and n - doped germanium . This results in an exchange of electrons and holes between the differently doped semiconducting materials . The n - doped germanium would have an excess of electrons, and the p - doped germanium would have an excess of holes . The transfer occurs until equilibrium is reached by a process called recombination, which causes the migrating electrons from the n - type to come in contact with the migrating holes from the p - type . A product of this process is charged ions, which result in an electric field . </Dd> <Dd> A difference in electric potential on a semiconducting material would cause it to leave thermal equilibrium and create a non-equilibrium situation . This introduces electrons and holes to the system, which interact via a process called ambipolar diffusion . Whenever thermal equilibrium is disturbed in a semiconducting material, the number of holes and electrons changes . Such disruptions can occur as a result of a temperature difference or photons, which can enter the system and create electrons and holes . The process that creates and annihilates electrons and holes are called generation and recombination . </Dd> <Dd> In certain semiconductors, excited electrons can relax by emitting light instead of producing heat . These semiconductors are used in the construction of light - emitting diodes and fluorescent quantum dots . </Dd> <Dt> Thermal energy conversion </Dt>

Which element is used extensively in semi condutor chips