ELECTRICAL CONDUCTION AND THERMIONIC EMISSION IN SEMI-CONDUCTORS
Abstract
Investigation was made of the electrical conductivity of crystalline ThOsub2 in different gases at atmospheric pressure. In general, the values of conductivity obtained when the crystal was heated in an H atmosphere followed the usual temperature dependence for a semiconductor: Sigma = A exp.(-eV/kT). The conductivity in O was noticeably higher. The effect of passage of current on conductivity and color was determined at 2 temperatures for crystals heated in O. The current passed at 675 deg C by the crystal with a fixed voltage applied increased with current-drawing time to a new equilibrium value. When the applied voltage was removed, the conductivity decayed to its original value. An even larger ratio of change was noted at 580 deg. When current was passed continuously through a ThOsub2 crystal heated in H, slight conductivity change occurred. If the atmosphere was charged from H to He, a conductivity increase of 2 orders of magnitude occurred at 680 deg when current was passed continuously. Efforts were made to determine whether H could enter the ThOsub2 crystal in sufficient quantities to cause bleaching and lowered conductivity. The most sensitive measurement attempted failed to show any weight change associated with the reddening of a crystal in O. The results indicated an upper limit of the amount of excess O in the neighborhood of 2 x 10 to the 17th power atoms/cc. of ThOsub2. Measurements of the gas evolved when a crystal was bleached in vacuum indicated that this figure is of the correct order.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1952
- Accession Number
- AD0000291
Entities
People
- D. L. Goldwater
- O. A. Weinreich
- W. E. Danforth