Electron spin resonance methods have been used to measure the temperature dependence of the spin-lattice relaxation time T1 of dangling bond electrons in hydrogenated amorphous silicon and silicon carbide samples prepared by radio frequency sputtering. The T1 measurements were made by a combination of continuous-wave absorption mode saturation and periodic adiabatic passage methods over the temperature range 100–400 K, yielding T−11∝T2 behavior consistent with relaxation by two-level systems.

This reproduction was made from a copy of a manuscript sent to us for publication and microfilming. While the most advanced technology has been used to pho tograph and reproduce this manuscript, the quality of the reproduction Is heavily dependent upon the quality of the material submitted. Pages In any manuscript may have Indistinct print. In all cases the best available copy has been filmed. The following explanation of techniques Is provided to help clarify notations which may appear on this reproduction. 1. Manuscripts may not always be complete. When It Is not possible to obtain missing pages, a note appears to Indicate this. A. Why Study Amorphous Materials? 1 B. Definitions of Amorphous State 2 C. Electronic Energy Bands in Amorphous Semiconductors 6 D. Dangling-bond Defects and Their Influence on Electronic Energy Bands in Amorphous Semiconductors 16 E. Hydrogenated Amorphous Silicon 21 F. Role of ESR in the Study of a-Si Based Materials and Description of the Present Work 31 II. BASIC ESR THEORY AND INSTRUMENTATION 39 A. General Description of ESR 39 B. Bloch Equations 48 C. Features of ESR Spectra 69 D. ESR Instrumentation 80 III. RELAXATION PHENOMENA 104 A. Various Mechanisms of Relaxation 104 B. Experimental Methods for the Determination of Spin-Lattice Relaxation Time T^ 110 IV. EXPERIMENTAL METHODS A. Samples B. Temperature Control 121 C. Dispersion Mode Data D. Continuous-wave Saturation Data 133 V. RESULTS AND DISCUSSION A. H^ Values Determined from Dispersion Mode Measurements B. Ti Values Determined from Continuous-wave Saturation Data C.

No abstract