M. Saito

Polarized (letter ‘8’) memory in CdSe point contact diodes

Abstract Polarized memory, i.e., the memory in which switching between ON and OFF states depends on the polarity of bias voltage has been found in point contact diodes on single crystals of CdSe, CdS, CdTe, GaAs and GaP. The detailed features of switching characteristics depend on the choice of metals for the point contact electrode, on the sharpness of the contact and also on the resistance of the current limiter in the circuit. Observation of the transients between ON and OFF has also been performed.

Observation of ‘ON’ and ‘OFF’ states of the polarized (letter ‘8’) memory effects in CdS and CdSe thin films

Abstract ‘ON’ and ‘OFF’ states of polarized memory effects in thin films of Au-CdS-Au and Au-CdSe-Au structures were observed. A current construction occurs and takes a new position in each switch-ON, and mass transfer occurs in this region.

Polarity dependent transport of Cu atoms in CdSe single crystal under electric field

Abstract In order to clarify the mechanism of polarized (letter ‘8’) memory in CdSe-Cu point contact diodes, transport phenomenon of Cu atoms in CdSe crystal has been investigated which is induced by electric field and strongly dependent on its polarity. Radioactive 64Cu experiment has also been performed to clarify the nature of low conductance of OFF state.

Observations of photovoltage in the polarized (letter ‘8’) memory effects in CdS thin films

Abstract Experiments of photovoltage and the temperature dependence of conductance is ON and OFF states of the polarized memory effect in SnO 2 —CdS—Au structure have been performed. These results suggest that a metallic path is formed in ON state, while the nature of thin film which depends on electrode metals appears in OFF state.

Observations of on and off states of the polarized memory effects in amorphous semiconductor films

Abstract Polarity dependent switching and memory effect, i.e., polarized memory effect, has been studied in amorphous thin films on SnO 2 coated glass. Observation of ON and OFF states of the effect has been performed. Appearance of damages manifested itself differently for ON-to-OFF and OFF-to-ON transients.

Polarized (letter ‘8’) memory effects in hetero-systems and non hetero-systems

Abstract In order to clarify whether or not the existence of the heterojunction is a necessary condition for the observation of polarized memory effect, experimental observation has been performed on heterosystems which have evaporated thin film on single crystal. The experiments on the reversal of switching polarity have also been carried out. The results suggest that heteojunctions are not essentially related to the polarized memory effect.

Anomalous effect in Au point contact on Cu-formed surface of CdSe single crystal

Abstract Voltage controlled negative resistance in one polarity and current controlled negative resistance in the other polarity were observed in the system of Au point contact on Cu-formed surface of CdSe single crystal. Result of thermoelectromotive force measurement on the Cu-formed region showed that p-type material was produced on the n-type surface of CdSe crystal. Au point contact experiments on Cu-formed and unformed surface of CdSe, and also on Cd-formed and unformed surface of Cu2−xSe were carried out.

Barrier lowering and sensitive current change in point contact semiconductor diodes caused by mechanical pressure

Abstract Sensitive current change in the reverse characteristic of semi-conductor point contact diodes caused by mechanical pressure on the contact has been investigated. Experimental evidences for the barrier height lowering by the increased mechanical pressure on the contact are obtained through the observation of the change in the open-circuited photovoltage Vph etc.

Polarized (letter ‘8’) memory effect in Si single crystal point contact diodes

Abstract In order to contribute for clarifying the mechanism of polarized memory effect, experimental observation on Si single crystal point contact diode has been studied. Thermoelectromotive force measurement has also been performed both for ON and OFF states.

Further evidence for the barrier lowering due to the mechanical pressure on p-type germanium point contact diode

Abstract Minority carrier injection ratio of the point contact diode decreases with the increase in the mechanical pressure exerted on the point contact in p-type Ge. The result seems to serve as an evidence for the barrier lowering effect which also causes the pronounced sensitivity in the pressure effect of the reverse current.