A novel technique for nano-scale lithography of cadmium selenide via a scanning tunneling microscope tip-induced reaction

In the introductory chapter the physical and interfacial properties of cadmium selenide are presented, as well as a discussion of select surface properties of CdSe. Also, a brief review of scanning probe lithographic techniques currently under investigation is presented.;As a portion of the project presented herein, a research-grade scanning tunneling microscope was constructed. The second chapter includes information specific to this instrument. Included are descriptions of the electrical components, descriptions of the mechanical components, and a description of the noise reduction and calibration of the instrument.;When cleaved-in-air (112¯0) CdSe is imaged repeatedly under humidified conditions, small (∼20 nm wide and between 6 Å and 12 Å in height) features are observed to form. The features are similar in shape to one another, suggesting tip imaging. Under an atmosphere of dried nitrogen feature growth is not observed. The growth of the features shows a strong dependence on both the tunneling current and the bias voltage. The initial rate of feature growth increases with tunneling current. Feature growth as a function of bias voltage displays an onset at a sample bias of −1. 2 V to −1. 3 V and is no longer observed at sample biases more negative than −2.5 V. Two possible models are presented for feature growth. The smallest feature observed is ∼6 nm in width.;The fourth chapter describes simple and inexpensive classroom demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). The demonstrations comprise common orienteering compasses, whose needles represent magnetic dipoles, along with three collinear permanent magnets, and a magnetic stir plate or pulseable electromagnets. The trio of permanent magnets provides a laterally uniform magnetic field, whose strength decreases with distance from the magnets. Resonance can be observed by adjusting the frequency of the magnetic stirrer when it is in close proximity to the compasses. Another demonstration involves pulsing electromagnets that apply a perpendicular magnetic field that causes the compass needles to oscillate.