Observation of a novel relaxation process associated with electronic transitions from deep (D) defects in hydrogenated amorphous silicon

Abstract

Junction capacitance transient measurements were employed to study the thermal emission of electrons trapped in deep (D) defects in lightly n-doped a-Si:H samples. We conclude that a novel defect relaxation process occurs upon a change of change state of the defect such that an electron's thermal release rate is inversely proportional to its residence time in the defect. Supplemental spin transient measurements indicate that both ${\mathit{D}}^{\mathrm{\ensuremath{-}}}$/${\mathit{D}}^{0}$ and ${\mathit{D}}^{0}$/${\mathit{D}}^{+}$ transitions must be involved. A good fit to our data is obtained if we assume a non-Markovian process for the ${\mathit{D}}^{0}$/${\mathit{D}}^{+}$ transition.