A correlation study between photodegradation and material quality in amorphous silicon p-i-n solar cells

In this work the authors focused on the possibility to derive correlations between p-i-n solar cells degradation and the material deposited inside the p-i-n, employing a capacitance versus frequency technique. Results obtained with this technique have been compared with those obtained by standard I-V characterization, and a complete picture of the density of states during light soaking has been obtained. This has been finally correlated with the initial features of the device. As a result, evidence of the presence of either neutral dangling bonds or quasi-shallow traps has been found. Degradation due to light soaking can be interpreted by a consistent increase of deep defects together with a much lighter effect on quasi-shallow defects