Es werden das V~iderstandstemperaturverhalten und die spektrale lichtelektrische Elektronenausbeute diinner im Uttrahochvakuum aufgedampfter Ge-Filme in verschiedenen Ordnungs-(Temperungs-)zust~nden gemessen. Die Widerstandsmessungen ergeben zwei Acceptorniveaus im Abstand 0,1 und 0,2 eV yon der Valenzbandkante. Ihnen entsprechen zwei Elektronenaustrittspotentiale yon etwa ~1 = 5,0 und ~02 = 5,t V. Der EinfluB yon Schichtdicke, Temperungszustand und MeBtemperatur auf Austrittspotential und Mengenkonstante werden ermittelt. Die zum h6heren Austrittspotential ~02 geh6rende Mengenkonstante ist bei 77 ~ K gr613er, bei 273 ~ K kleiner als die zum niedrigeren Austrittspotential ~1 geh6rende.

Ge-films are evaporated under high vacuum conditions at 77°K. They are investigated either in the disordered state (before annealing at a higher temperature) or in the ordered state after annealing. The electric resistance R and the photoelectric work function Φ are measured before and after the influence of known amounts of carbon monoxide. R is plotted as a function of time and coverage n, Φ as a function of n. At 77°K an electronic interaction between the CO molecules and the Ge-film follows from an observed irreversible and reversible increase in R; Φ is not altered. The discussion by means of a band model shows that the CO molecules act as electron donors. At room temperature no interaction is found. Films precovered with oxygen show two simultaneous reactions during the adsorption of CO: a stronger adsorption on the spots precovered with oxygen and a weaker one on the bare Ge surface.

Ge films of thicknesses within the p-boundary layer thickness are precipitated under ultra high vacuum conditions, at 77 °K. They are investigated either in the disordered state (before annealing at a higher temperature) or in the ordered state (after annealing). The electric resistance R and the photoelectric work function are measured before and after the influence of known amounts of oxygen. R is plotted as a function of time and coverage n, <£> as a function of n. Small amounts of oxygen cause R to increase without changing large amounts result in a succeeding decrease of R and cause to increase by 0.1 to 0.2 V. The results are discussed by means of a band model. At small coverages oxygen acts as an electron donator, at higher coverages as an electron acceptor.