Contribution to the Theoretical and Experimental Study of the Electron-volt Effect in the N-P Junctions; CONTRIBUTION A L'ETUDE THEORIQUE ET EXPERIMENTALE DE L'EFFET ELECTRON-VOLTAIQUE DANS LES JONCTIONS-N.P.
Thesis submitted to Univ. of Paris. The proposed sim of this work was to study the behavior of a semiconducting junction under the action of BETA radiation. These studies were directed on the one hand to direct conversion of the energy radiated by a radioactive source of electric energy utilizable by means of n-p junctions and on the other hand to the kinetics of defects produced in the semi-conductor crystals by high-energy BETA rays. In the first part of this work, an sttempt was made to complete the earlier theories of the electron- volt effect in junctions by analyzing the effect mathematically. This led to a single equation containing the electrical and geometric parameters of the semicondactor and of the junction and the properties of the incident radiation. Apart from this, the diffusion current of the charge carriers created by the bombardment was studied in more detail, taking into account all the factors that play a part in the expressicn of the efficiency of charge collection of a junction. In the second part, where experiments on the irradiation of n-p junctions were carried out with a Sr/sup 90/-Y/sup 90/ source, mention is made of the particular advantages of a gallium arsenide junction capable of operating at relatively high temperatures (in the region of lOO deg C). The third part presents the study of defects created in a semiconductor crystal by high-energy BETA rays, according to the method of electron-volt effect. It is shown that from a study of the degradation of the short-circuit current of the junction it may be possible to determine the recombination level and the probabilities of electron and hole capture, as from a study of the lifetime decay of minority carriers in a crystal of known type. Experiments on the bombardment of Ge junctions by 2-Mev elcctrons were performed with a Van de Graaff. Very clear anomalies of the electron-volt effect at lOO deg K were observed. An attempt was made at interprethation of these anomalies in the junction, thaking into account other phenomena which occur at low temperature. In the fourth pant, results concerning the healing of the defects and protection measures against too energetic BETA rays are described. A healing difference was observed between the lifetime and the conductivity. Finally, interesting resulte were obtained from experiments using a cadmium sulfide film to transfonm the BETA particles of Sr/sup 90/-Y/sup 90/ into photon s. (auth)
- Research Organization:
- France. Commissariat a l'Energie Atomique. Centre d'Etudes Nucleaires, Saclay
- NSA Number:
- NSA-15-011697
- OSTI ID:
- 4084002
- Report Number(s):
- CEA-1443
- Country of Publication:
- France
- Language:
- English
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