Deep-level traps ordeep-level defects are a generally undesirable type of electronic defect insemiconductors. They are "deep" in the sense that the energy required to remove an electron or hole from the trap to thevalence orconduction band is much larger than the characteristic thermal energykT, wherek is theBoltzmann constant andT is the temperature.[1] Deep traps interfere with more useful types ofdoping bycompensating the dominantcharge carrier type, annihilating either free electrons orelectron holes depending on which is more prevalent. They also directly interfere with the operation oftransistors,light-emitting diodes and other electronic and opto-electronic devices, by offering an intermediate state inside the band gap. Deep-level traps shorten thenon-radiative life time of charge carriers, and—through theShockley–Read–Hall (SRH) process—facilitate recombination ofminority carriers, having adverse effects on the semiconductor device performance. Hence, deep-level traps are not appreciated in many opto-electronic devices as it may lead to poor efficiency and reasonably large delay in response.
Commonchemical elements that produce deep-level defects insilicon includeiron,nickel,copper,gold, andsilver. In general,transition metals produce this effect, while light metals such asaluminium do not.
Surface states andcrystallographic defects in the crystal lattice can also play role of deep-level traps.
 | This electronics-related article is astub. You can help Wikipedia byadding missing information. |
