Defect level spectroscopy - thermal emission energies

3 Defect level spectroscopy - thermal emission energies 

In measurements of the defect energies, it is essential to distinguish between the thermal emission and optical transition energies, to account properly for lattice relaxation effects (see Section 

Thermal emission measurements are generally based on electrical transport and in most cases involve the effects of a trapped space charge, Q. The two main ways of extracting information about the density of states distribution are from the release time of the charge from the traps 

The first of these approaches is used in the technique of deep level transient spectroscopy (DLTS), which is perhaps the most common experiment for measuring deep levels in crystalline semiconductors (Lang 1974). The DLTS experiment is the measurement of the transient capacitance of a Schottky contact to the sample and is 

15 illustrates the depletion layer of a Schottky barrier on an n-type semiconductor under zero and reverse bias. The depletion layer of width W V) constitutes an insulating layer bounded by the metal contact on one side and the conducting semiconductor on the other, and so behaves as a parallel plate capacitor, with capacitance sCo/lF per unit area. The width of the depletion layer is given by Poisson s equation. 

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