Refinements in the method of moments for analysis of multiexponential capacitance transients in deep-level transient spectroscopy

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Abstract
The analysis of multiexponential capacitance transients that arise in deep-level transient spectroscopy has been examined. The method of moments, a technique that provides a reliable method for resolution of a multiexponential capacitance transient into its exponential components, has been adapted and enhanced by incorporating an initial fast Fourier transform to extract the base-line offset, and a refinement in the cutoff correction to the moments integrals which improves convergence and accuracy. In addition, the mean displaced ratio smoothing algorithm has been incorporated and shown to improve the method’s accuracy in the presence of noise. For the case where the response is not significantly convoluted with the excitation, a simplified form of the method of moments technique provides a simple and more direct determination of the exponential components. Examples of results for simulated data are provided illustrating application of the analysis. The limitations of the technique in determining the number of exponential components, their amplitudes and emission rates, and the applicability of the smoothing algorithm are discussed.