Nanocrystalline Si-Based Resistive Humidity Sensors Prepared via HWCVD at Various Filament Temperatures
The growth of nanocrystalline Si on glass substrates via hot-wire chemical vapor deposition (HWCVD) at various filament temperatures and the fabrication of nanocrystalline Si-based resistive humidity sensors are reported. Experimental results indicate that the average diameter of nanocrystalline Si particles increases with increasing filament temperature. Measurements of the resistivity change of samples with humidity at 25°C show that the sensor response of samples fabricated at high filament temperatures is lower than that of samples fabricated at low filament temperatures. The sensitivity of the sensor increases with relative humidity.
Low temperature growth and structural characterization of nanocrystalline silicon films
Abstract Growth of nanocrystalline silicon films at substrate temperatures below 210°C using SiCl 4 /H 2 in a hot-wire chemical vapor deposition (HW-CVD) reactor is reported here. Raman spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to investigate the microstructure of the silicon films. TEM analyses reveal that nanocrystalline silicon film with grain sizes in a range 7–10 nm was deposited at a substrate temperature of 150°C. A 45-nm-thick amorphous interfacial layer was formed on the glass substrate prior to the nanocrystalline film. Raman scattering measurement determines that the deposition of nanocrystalline silicon film with a 90% crystalline fraction is achieved at 150°C. A nanocrystalline film with a 77% crystalline fraction is formed at a substrate temperature of 90°C. The advantages of this process and roles of Cl and H radicals in the formation of crystalline silicon films are discussed.
Timber, its nature and behaviour
Preface. Acknowledgements. Chapter 1 - Structure of Timber. Chapter 2 - Appearance of Timber in Relation to its Structure. Chapter 3 - Mass Volume Relationships. Chapter 4 - Movement in Timber. Chapter 5 - Flow in Timber. Chapter 6 - Deformation Under Load. Chapter 7 - Strength and Failure in Timber. Chapter 8 - Durability of Timber. Chapter 9 - Processing of Timber. Index.