Memory characteristics of p type-germanium/n type-cadmium-sulphide heterojunctions

The V/I characteristics of p Ge-n CdS heterojunctions exhibit a hysteresis or memory characteristic which is the result of two diode conduction states of resistances 106 and 10¿. The device switches from the high to the low state in less than 30 ns under reverse bias, and resetting to the high-resistance state occurs in less than 100 ns when a threshold forward bias current is exceeded. In either state, the device retains its state for periods greater than two weeks and appears to have potential application as a fast, nonvolatile memory element.