High Field Domains in CdS Crystals Moving in the Anode‐Cathode Direction

Abstract

High field domains in low conductivity CdS crystals moving with low velocities to 10 cm/s) from the cathode to the mode (cta layers) were first described by Boer, Hlinsch, and Kiimmel (1). A theoretical study made by BSer and Wilhelm (2) showed that the cta layers under discussion are probably caused by field quenching.Detaiied experimental investigations of the cta layers have shown that in special cases in the "mainff domains moving from the cathode to the anode "subdomainsv1 are observable which move in the opposite direction (3, 4). In this paper high field domains in CdS crystals of low conductivity are reported and discussed which move from the anode to the cathode (atc layers) including as a special case the earlier observed subdomains in the cta layers.Vapour phase grown plate-shaped CdS crystals were Cu doped and contacted with gold (electrode distance 1.5 to 2 mm). The electrooptical method was used as proposed in (5) to make the high field domains visible. The domains could be observed microscopically or detected by a multiplier.The main characteristics of the atc layers and the conditions for the appearance of these layers are the following: a) The atc layers appear above an electric field strength (15 to 20 kV/cm) which is about twice the critical field for appearance of the cta layers. Always several atc layers are observed following each other at nearly the same distance ( LI 0.1 mm). In some crystals 10 to 15 layers move simultaneously. The impression given by atc domains is similar to a moving interference pattern. The boundaries of the atc layers are not as sharp as those of the cta layers. The difference between the maximum and the minimum field strength 1) Guest from the Faculty of physics, University of Sofia.8 physica

Transition between Stationary and Moving High‐Field Domains in CdS in a Range of N‐Shaped Negative Differential Conductivity due to Field‐Quenching

“…A/cm2 current instabilities grow large enough to make the transition to jmov and free moving domains occur [15]. These domains are believed to occur because of geometry induced field inhomogeneities at the anode.…”

“…5 for as in Fig. 5, however curves 1 to 9 are corrected [15]. These domains are believed to occur because of geometry induced field inhomogeneities at the anode.…”

Experimental study on the velocity and the shape of high field domains moving in the anode–cathode direction in CdS crystals

“…Some characteristics of the ac layers and their appearance in low conductivity crystals have been given in the previous paper [4]. It is the purpose of this paper ac domains in low conductivity (10-11 C2-1 cm-1 5 o 5 t o present further experimental results on the main parameters of the domains :…”

“…These domains move in the opposite direction (ac domains or ac layers). ac domains were observed moving within ca layers and were called subdomains [2, 31, but later on it was shown that these two types of high field domains can appear in CdS crystals independently of each other [4].…”

“…C2-l cm-l) CdS single crystals were described in [4]. The ac layers appear above an electric field strength of 15 to 20 kV/cm and are not connected with any non-linearity of the current-voltage characteristics.…”