Electron spin resonance defect signal

An underlying question in many of the ESR measurements of the lineshape of the N-donor and its temperature dependence is the possible existence of an additional broad line at a similar g-value to the three-line spectrum. Most authors agree that the three lines in the isolated N-donor spectrum should have symmetric lineshapes and, since there is a slight asymmetry to the full spectrum, this leads to the conclusion that there is another relatively broad ESR line shifted slightly from the three-line spectrum. This could be due to a second donor, a conduction electron spin resonance or a structural defect. A weak signal, possibly due to a Si vacancy, is also observed at higher temperatures (T > 50 K) in some samples. 

It is obviously of interest to know whether the deep trap observed in DLTS is the same as the g = 2.0055 ESR defect and two different experiments have confirmed this. Both use the DLTS approach, but measure ESR in combination with the capacitance (Cohen, Harbison and Wecht 1982, Johnson and Biegelsen 1985). When a reverse bias is applied to n-type a-Si H there is a transient increase in the spin density of the 2.0055 resonance. The temperature dependence of the transient spin signal is identical to that found in the usual DLTS experiment. The interpretation is that a 2.0055 spin occurs whenever an electron is released from the deep trap, so that the trap can be identified with the doubly occupied charge state of the defect. The other experiment made... 

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