Electrical conductance variation of a-Si: H films during a temperature programmed desorption

• Published in: The Journal of physics and chemistry of solids 1993-09, Vol.54 (9), p.1009-1014
• Main Authors: Aoucher, M., Mohammed-Brahim, T., Fortin, B., Colin, Y.
• Format: Article
• Language: English
• Subjects: activation energy; amorphous semiconducting film; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; gas-solid adsorption; gas-solid desorption; oxidation; Physics; Surface reaction
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/0022-3697(93)90006-D

In this investigation we report on the conductance of a Si: H filins during a temperature programmed desorption (Δ G-TPD) following an isothermal adsorption of molecular oxygen. Experimental conditions which give a restoration of the conductance vs temperature characteristics are described. A model of the conductance variation of an a-Si: H film, in the presence of ionosorbed species is proposed to fit the Δ G-TPD curves. lonosorption of oxygen on a-Si:H films shows the existence of traps located at 0.66 ± 0.03 eV, below the bottom of the conduction band, close to the Fermi level at the surface, with a frequency factor 7 ± 3 × 10 4 Hz. The initial density of adsorbed particles is estimated between 10 10 and 10 11 cm −2.