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The film properties of hydrogenated amorphous silicon (a-Si:H) prepared by glow-discharged (GD) decomposition of silane under visible-light illumination is reported. The defect density depends exponentially on the intensity of incident visible light.

A constant photocurrent method (CPM) was used to study the deep effect states in undoped a-Si:H. Two types of defect states were detected via CPM spectra: ST1, which is a neutral Si dangling-bond state; and ST2, which is a negatively-charged dangling-bond like defect state found in the lower gap. ST2 has a narrower full width at half-maxumim than ST1 and lies deeper in energy by .1 eV. Results also showed that long exposure to light increases the density of ST1 and decreases the density of ST2, implying that defect conversion occurs and proceeds during illumination.

Reduction of junction leakage currents is important to exactly obtain the energy distribution of gap states in hydrogenated amorphous silicon (a-Si:H) by post-transit photocurrent spectroscopy (PTPS). A double-layer transparent conducting gate composed of indium-tin-oxide (ITO) and silicon oxide (SiOx) is an effective means for this purpose in Schottky barrier sSBd diodes. However, there has been some concern that the presence of the SiOx layer could affect the PTPS results. We demonstrate from careful experimental studies that the insertion of the SiOx layer between ITO and a-Si:H does not give any additional structure in the energy distribution of gap states of a-Si:H measured by PTPS and the SB diodes with the ITO-SiOx double-layer gate are suited for exact PTPS measurements. [ABSTRACT FROM AUTHOR]

Post-transit photocurrent spectroscopy (PTPS) has been employed as an effective method to obtain the energy distribution of gap states in undoped hydrogenated amorphous silicon. In this article, we demonstrate that the simplifying assumptions in conventional PTPS related to the trap occupation are not always valid and special care should be taken when we extend PTPS to samples with larger leakage currents and/or high-defect densities. We show test diode structures and experimental conditions to exactly determine the energy distribution of both electron and hole trap states in these cases. The attempt-to-escape frequency, ν, both for electrons and holes has been evaluated from the temperature dependence of the characteristic points in PTPS signal. It has been found that the density of electron and hole trap states in the deeper energy range increases with long exposure to visible light while the density in the shallower energy range decreases, which suggests the occurrence of defect conversion. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The insertion of the SiOx layer between indium-tin-oxide (ITO) and alpha-Si:H does not give any additional structure in the energy distribution of gap states of alpha-Si:H measured by the post-transit photocurrent spectroscopy is demonstrated. A method for determining the recombination parameters of iron-boron pairs in silicon by analyzing the crossover points is presented.

Presents information on a study which investigated the electrical characterization of amorphous silicon (a-Si:H) using a liquid Schottky barrier. Advantages of using the surface photovoltage method using a liquid Schottky barrier; Properties of a-Si:H and crystalline (c) Si contacts with redox couple of quinone-hydroquinone; Application of capacitance-voltage measurements in liquid Schottky barrier diodes.

Presents a study which performed experiments to characterize hydrogenated amorphous silicon (a-Si:H) prepared by alternatively repeating chemical-vapor deposition (CVD) from disilane and hydrogen plasma (HP) treatment. Details on the light-induced instability in a-Si:H; Details of an experiment on a-Si:H; Summary of structural and optoelectronic properties of CVD a-Si:H; Description of the energy distribution of deep defect states of a HP treated CVD a-Si:H.

Presents a study which investigated the properties of hydrogenated amorphous silicon prepared by glow discharge decomposition of silane with visible light illumination on a growing surface. Experimental details; Results and discussion; Conclusion.