Carbon Contamination Measurements in Single Silicon Crystals

Carbon Contamination Measurements in Single Silicon Crystals

Date: December 1970
Creator: Logsdon, Lawrence E.
Description: The intent of this investigation was to directly measure the amount of carbon contamination in a single silicon crystal and, in so doing, develop a mathematical procedure that would be applicable to other contaminants in other substances.
Contributing Partner: UNT Libraries
Composting technologies, costs, programs, and markets

Composting technologies, costs, programs, and markets

Date: January 1989
Creator: CAL Recovery Systems, Inc.
Description: This report provides an overview of the technology of composting which involves three major steps: 1) the preparation of the raw material, 2) the compost process itself, and 3) the grading of the final product.
Contributing Partner: UNT Libraries Government Documents Department
Electronic and field emission properties of boron nitride/carbon nanotube superlattices

Electronic and field emission properties of boron nitride/carbon nanotube superlattices

Date: July 1, 2002
Creator: Meunier, Vincent; Roland, Christopher; Bernholc, Jerry & Buongiorno Nardelli, Marco
Description: Article on electronic and field emission properties of boron nitride/carbon nanotube superlattices.
Contributing Partner: UNT College of Arts and Sciences
Investigation of Selected Optically-Active Nanosystems Fashioned using Ion Implantation

Investigation of Selected Optically-Active Nanosystems Fashioned using Ion Implantation

Date: May 2006
Creator: Mitchell, Lee
Description: Opto-electronic semiconductor technology continues to grow at an accelerated pace, as the industry seeks to perfect devices such as light emitting diodes for purposes of optical processing and communication. A strive for greater efficiency with shrinking device dimensions, continually pushes the technology from both a design and materials aspect. Nanosystems such a quantum dots, also face new material engineering challenges as they enter the realm of quantum mechanics, with each system and material having markedly different electronic properties. Traditionally, the semiconductor industry has focused on materials such Group II-VI and III-V compounds as the basis material for future opto-electronic needs. Unfortunately, these material systems can be expensive and have difficulties integrating into current Si-based technology. The industry is reluctant to leave silicon due in part to silicon's high quality oxide, and the enormous amount of research invested into silicon based circuit fabrication. Although recently materials such as GaN are starting to dominate the electro-optical industry since a Si-based substitute has not been found. The purpose of the dissertation was to examine several promising systems that could be easily integrated into current Si-based technology and also be produced using simple inexpensive fabrication techniques such ion implantation. The development of optically active ...
Contributing Partner: UNT Libraries
Making a Difference

Making a Difference

Date: August 29, 2014
Creator: Parsons, John
Description: Lesson plan containing a collection of activities and resources regarding making a difference and that meet state education standards and national sustainability standards for the 4th grade level.
Contributing Partner: UNT Office of Sustainability
L-Shell X-Ray Production Cross Sections for ₂₀Ca, ₂₆Fe, ₂₈Ni, ₂₉Cu, ₃₀Zn, ₃₁Ga, and ₃₂Ge by Hydrogen, Helium, and Lithium Ions

L-Shell X-Ray Production Cross Sections for ₂₀Ca, ₂₆Fe, ₂₈Ni, ₂₉Cu, ₃₀Zn, ₃₁Ga, and ₃₂Ge by Hydrogen, Helium, and Lithium Ions

Date: May 1992
Creator: McNeir, Michael Ridge
Description: L-shell x-ray production cross sections are presented for Fe, Ni, Cu, Zn, Ga, and Ge by 0.5- to 5.0-MeV protons and by 0.5- to 8.0-MeV helium ions and Ca, Fe, Ni, Cu, and Ge by 0.75- to 4.5-MeV lithium ions. These measurements are compared to the first Born theory and the perturbed-stationary- state theory with energy-loss, Coulomb deflection, and relativistic corrections (ECPSSR). The results are also compared to previous experimental investigations. The high precision x-ray measurements were performed with a windowless Si(Li) detector. The efficiency of the detector was determined by the use of thin target atomic-field bremsstrahlung produced by 66.5 keV electrons. The measured bremsstrahlung spectra were compared to theoretical bremsstrahlung distributions in order to obtain an efficiency versus energy curve. The targets for the measurement were manufactured by the vacuum evaporation of the target element onto thin foils of carbon. Impurities in the carbon caused interferences inthe L-shell x-ray peaks. Special cleansing procedures were developed that reduced the impurity concentrations in the carbon foil, making the use of less than 5 μg/cm^2 targets possible. The first Born theory is seen to greatly overpredict the data at low ion energies. The ECPSSR theory matches the data very well at ...
Contributing Partner: UNT Libraries