Investigations of the thermally stimulated exoelectron emission (TSEE) from aluminium surfaces

The TSEE from aluminium surfaces is excited by irradiation with electrons. Exposure of the exoemissive surfaces to water vapour yields different excitation conditions (energy losses and absorption of the exciting electrons) and different emission conditions (absorption of exoelectrons, work function changes of the surfaces) dependent on the thickness of the sorption layer. After argon ion bombardement of oxide and gas-covered surfaces the electron excited TSEE may be reduced almost to the detection limit. After sorption or oxidation, the emissive power increases again. With experimentally checked suppositions, TSEE curves of the various participating species of emission centres are calculated and compared to the measurements. From this comparison and from measured energy distributions of the exo-electrons follows that the TSEE cannot be described by an instationary thermionic emission. Accelerating electric fields in consequence of charging of the surface can also be excluded.