THE DISCONTINUITY IN THE CONDUCTIVITY CHARACTERISTICS OF UNDOPED A-SI-H-STATISTICAL SHIFT OR METASTABILITY

The authors have tested two explanations for the discontinuity-or 'kink'-in the DC conductivity versus 1/T characteristics of undoped a-Si:H. The statistical shift of the Fermi level leads one to predict the kink qualitatively but it is more difficult to see how it can be used in accounting for the data quantitatively. On the other hand, thermal equilibrium processes, although not quantitative, provide a general explanation for discontinuities in both doped and undoped a-Si:H. From the experimental tests carried out the authors infer that, although a contribution from the statistical shift cannot be excluded, the most likely cause of the kink is the metastability.