| 摘要 |
1,253,700. Semi-conductor switching device. ENERGY CONVERSION DEVICES Inc. 3 March, 1969 [4 March, 1968], No. 11121/69. Heading H1K. A device consisting of a mixture of sulphur and a transition element disposed between ohmic contacts exhibits high resistance up to a threshold voltage. When this voltage is exceeded it switches rapidly to a low-resistance condition but reverts when the current falls below a holding valve. With A.C. switching occurs in each half cycle. The preferred material consists of 20-33À3 atomic per cent vanadium and the remainder sulphur. It is made by heating a mixture of the powdered elements for 24 hours at 400‹ C. in a sealed quartz tube. The resulting black powder can be used in that form, compacted into pellets, or applied in a paint or sputtered on to the electrodes which are suitably of graphite, niobium, tantalum, molybdenum or tungsten. The material is believed to be in an amorphous or crystalline polymeric form. |
