Some Observations of Space Charge Limited Current in Cadmium Sulphide Crystals

Autor: A A Kayali, D J Page, G T Wright
Rok vydání: 1962
Předmět:
Zdroj: Proceedings of the Physical Society. 80:1133-1142
ISSN: 0370-1328
Popis: Space-charge-limited current in solids has been studied experimentally in crystals of cadmium sulphide. Accurate compensation of trapping defects has been achieved and the fundamental Child's square law for solids has been verified experimentally over a temperature range from 77° to 400 °K. Under space-charge-limited conditions the density of charge carriers available for current is independent of temperature; current is proportional to carrier mobility and provides a means of studying this quantity directly. By observing Child's law over the whole temperature and voltage range of interest it may be ensured that true space-charge-limited conditions are existing and consequently that reliable and accurate information is obtained. An insulator crystal provided with an emitting contact and a collector contact forms a dielectric diode. The emitting contact is a space-charge cloud of mobile carriers which is experimentally reproducible and is amenable to quantitative theoretical description; accordingly, the experimental characteristics of the diode are determined by the physical nature of the collector contact which is made in the normal manner. It is therefore possible to investigate experimentally the properties of a single contact. Rectification characteristics have been measured and compared with theory for a number of diodes over ranges of current covering nine orders of magnitude. The straightforward concept of a contact as two different sets of energy levels simply butted together is remarkably well vindicated.
Databáze: OpenAIRE