Elektronenmikroskopische Oberflächenuntersuchungen an CdS‐Einkristallen

Abstract

Oberflächenabdrucke von unbehandelten sowie von verschiedenen Behandlungen unterworfenen CdS‐Einkristallen wurden elektronenmikroskopisch bei 12000‐facher Vergrößerung untersucht. An Behandlungsverfahren wurden Temperungen im Hochvakuum, Bestrahlungen mit hohen Lichtintensitäten und Beschuß mit Ionen einer H2‐Gas‐entladung angewendet. Die Oberflächen der unbehandelten Kristalle zeigten in der Regel eine Belegung mit Teilchen, die eine Größe von maximal 1 μm besaßen. Eine Temperung der Kristalle im Hochvakuum führte im allgemeinen zu einer Abnahme der Teilchendichte, während bei intensiver Belichtung stets eine Zunahme der Teilchendichte beobachtet wurde. Bei Ionenbeschuß bildete sich eine polykristalline Kadmiumschicht aus. Die beobachteten Teilchen werden als Kadmiumabscheidungen gedeutet.

Photovoltaic Effects at Rectifying Junctions to Deposited CdS Films

“…The short free-hole diffusion length in CdS would confine all photovoltaic effects to the spacecharge layer, and hence any photoresponse would be a sensitive function of the depletion layer width, which, in turn, is dependent on the electrode metal's work function. 4 No evidence is found in any of the samples of the presence of photoemission of electrons from the metal as found by Williams and Bube (7). There is in all the curves a background which could be interpreted according to Williams and Bube's theory, but no simple relation has been found between the responses obtained from samples with differing thicknesses of the metal layer and between the metal forming the junction and the shape of the curve.…”

“…Berger et at. (4) have explained measurements on CdS films which were heat treated in vacuum by postulating the presence of two competing processes. The first is the diffusion of excess Cd to the surface where it is vaporized, and the second is the creation of sulfur vacancies near to the crystal surface owing to CdS dissociation.…”

“…This behavior is quite different from that reported for growth of silicon in windows [e.g., ref. (4)], where lateral overgrowth has not been reported. Since this phenomenon of overgrowth appears to be not only novel but also potentially useful for device fabricatien, it has been further investigated.…”

Structural and transport properties of thermally evaporated nickel phthalocyanine thin films

“…The mobility was observed to increase with increasing film thickness. This may be explained by an argument proposed by Berger et al [27], in which increasing film thickness is accompanied by an increase in mean crystallite size, thus reducing the number of internal potential barriers. The total trapping concentration N t was estimated from the measured slopes together with equation (12).…”