Characterization of CdTe/n$^{+}$ -Si Heterojunction Diodes for Nuclear Radiation Detectors
CdTe/n+-Si heterojunction diodes were fabricated and characterized for the development of gamma ray detectors. With the careful control of the growth parameters thick single crystal CdTe epilayers of high-crystalline quality were grown directly on the (211) Si substrates in a metalorganic vapor phase epitaxy. The heterojunction diode was fabricated by growing a 5 mum thick n-type CdTe buffer layer on the n+-Si substrate, followed by the growth of 100 mum thick undoped p-CdTe layer. The diode fabricated showed very good rectification property with a low value of the reverse bias leakage current, typically 1.26 times 10-7 A/cm2 for an applied reverse bias of 60 V. The diode clearly demonstrated the gamma radiation detection capability by resolving energy peaks from the 241Am radioisotope during the radiation detection test performed at room
Characterization of large single-crystal gamma-ray detectors of cadmium zinc telluride
The need for large, room-temperature gamma-ray spectrometers to be fabricated from a single crystalline section of a cadmium zinc telluride (CZT) boule was recently met by progress in crystal growth of high-resistivity material. The characterization of such large crystals provides us with an opportunity to better understand the detector physics and apply characterization techniques, which were difficult to implement and analyze on smaller crystals. In this study, metal-semiconductor-metal, planar-CZT detectors were fabricated from large (approximately 9 × 9 × 6 mm3), CZT single crystals. We have investigated the relationship between the results of the electric-field mapping via Pockels effect, photoconductivity data, and detector performance. Changes in the surface recombination and device characteristics showing departure from symmetry are caused and revealed by variations in the surface preparation.
Nietzsche's Task: An Interpretation of Beyond Good and Evil
When Nictzsche published Beyond Good and Evil in 1886, he told a friend that it was a book that would not be read properly until "around the year 2000". Now Laurence Lampert sets out to fulfill this prophecy by providing a section by section interpretation of this philosophical masterpiece that emphasises its unity and depth as a comprehensive new doctrine on nature and humanity. According to Lampert, Nietzsche begins with a critique of philosophy that is ultimately affirmative, because it shows how philosophy can arrive at a defensible ontological account of the way of all beings. Nietzsche next argues that a new post-Christian religion can arise out of the affirmation of the world disclosed to philosophy. Then, turning to the implications of the new ontology for morality and politics, Nietzsche argues that these can be reconstituted on the fundamental insights of the new philosophy. Nietzsche's comprehensive depiction of this anti-Platonic philosophy ends with a chapter on nobility, in which he contends that what can now be publicly celebrated as noble in our species are its highest achievements of mind and spirit.