Minimum Carrier Research Articles

A rapid evaluation technique for functional Gunn diodes

A rapid technique for estimating the carrier mobility, average and minimum carrier concentration, and contact resistance in operational Gunn diodes is presented. Although the physical nature of the functional Gunn-effect device (i.e., an n-type active layer with only two n+ohmic contacts) restricts what can be measured, it will be shown that information useful for estimating device performance can be obtained if some simplifying assumptions are granted. The procedure is illustrated by data obtained from five separate wafers of vapor-phase, epitaxially grown gallium arsenide.

Nonisothermal Conduction in Indium Antimonide with Orthogonal Electric and Magnetic Fields

A nonisothermal analysis of dc conduction in n- and p-type indium antimonide subjected to orthogonal electric and magnetic fields has been developed including the effects of energy-dependent acoustic phonon and polar optical phonon scattering as well as minority carrier drift. Also, included are carrier generation, based on an equilibrium between carrier densities and particle temperatures, magnetoresistive effects and carrier injection. Threshold microwave emission curves are calculated assuming that a minimum minority carrier density is required to observe shot noise. The threshold curves give general agreement with the experimental results. When the distortion of the field due to the Hall effect is included, excellent agreement between theoretical and experimental curves is obtained.

Effect of small doses of carrier iodide upon the organic binding of radioactive iodine by the human thyroid gland.

ABSTRACT The effect of small doses of carrier iodide (127I′) upon the organic binding of radioactive iodine (131I) by the thyroid gland has been studied by performing 123 perchlorate discharge tests in normal persons and patients with abnormal thyroid function. In 86 tests, 100–2000 μg 127I′ was given with the iv 131I dose; the remaining 37 tests without carrier served as controls. In 60 of the 86 tests in which carrier iodide was administered, there was a positive perchlorate discharge of 131I from the thyroid gland, indicating that organic binding of iodine was impaired. In the 37 control tests, perchlorate discharge was observed only in 2 patients with untreated thyrotoxicosis. Although there was considerable individual variation, the minimum carrier dose of 127I′ required to cause demonstrable block of organic binding in normal persons appeared to be of the order of 750 μg, which resulted in a serum iodide level of 30–38 μg/1. However, a positive perchlorate discharge was observed in 1 of 3 TSH-treate...