Low Dark Conductivity Research Articles

Preparation of highly photosensitive hydrogenated amorphous Si-Ge alloys using a triode plasma reactor

Highly photoconductive hydrogenated amorphous Si-Ge alloys have been prepared from a SiH4/GeH4 gas mixture using a triode glow-discharge reactor. High photoconductivity (Δσp≂10−4 Ω−1 cm−1) under the AM1 (100 mW/cm2) illumination and low dark conductivity (σd=10−8–10−9 Ω−1 cm−1) have been obtained for the optical gap in the range between 1.5 and 1.7 eV.

Enhanced photoconductivity in nitrogen-doped amorphous silicon prepared by d.c. sputtering

Abstract Amorphous silicon, prepared by d.c. sputtering in a hydrogen/argon mixture, has been obtained with a low dark conductivity (10−10 Ω1 cm−1) at room temperature and a high photoconductivity. Moreover, a high-level doping has been achieved by the introduction of nitrogen in the plasma during the sputtering process. This doping displaces the Fermi level to within 0.1 eV of the conduction band edge and enhances the photoconductivity by several orders of magnitude.

Transport of excess charge in electron-irradiated dielectrics

Irradiation of dielectrics with nonpenetrating electron beams has been used for practical purposes, e.g., manufacturing of electrets, and as a research tool, e.g., the investigation of induced conductivity and transport properties. The present paper develops some aspects of the theory of charge transport and storage and radiation-induced conductivity in irradiated dielectrics. It is assumed that the dielectric is kept in short circuit and that the range of the incident electron beam is smaller than half the sample thickness. The treatment applies only to dielectrics which have a very low dark conductivity and contain a great number of deep traps.

Preparation and properties of silicon-cadmium selenide p-n heterojunctions

The vacuum deposition of thin (0.3–0.6 μm) n-CdSe films on p-Si substrates is described, together with an evaluation of the heterojunction properties. Results obtained using both pulsed and steady state light conditions are reported. The devices show in the reverse direction, i.e. with the top electrode biased positively, a low dark conductivity (σ≅1.5 × 10−6 mho cm−2) and a high dark-to-light resistance ratio (ϱDϱL > 104 at 1.0 V). In this mode of operation, the properties of the heterojunction, rather than those of the photoconductive film, determine the over-all device behavior, as evidenced by the fast rise and decay times (< 3 μsec) and the low values of the photoconductive gain (≅0.25). These and other results can be related to the properties of the constituent semiconductors.

A Mercuric Iodide Gamma-Ray Spectrometer

Crystals of HgI2 (Eg = 2.1 eV) have been operated as conductign type Ω-ray spectrometers at room temperature. Two-carrier collection is observed and collection of the electrons is sufficiently good to give full energy peaks for γ-rays of energies below 100 keV. A resolution of 10 keV FWHM was observed for the 18 keV X-ray from 241Am Room temperature spectroscopy in the energy region < 100 keV is possible due to the high stopping power of HgI2 (Z = 80, 53) and the low dark conductivity {~10-13(Ω. cm)-1). With the present material the mobility-lifetime product is 10-5 to 10-4 cm2/V for electrons and is 10-6 to 105 cm2/V for holes.