High-efficiency and low dark current crystalline selenium-based heterojunction photodiode with a high-quality tellurium nucleation layer
In this study, a high-efficiency and low dark current thin-film crystalline selenium (c-Se)/gallium oxide (Ga2O3) heterojunction photodiode is demonstrated via improving the deposition conditions for the tellurium nucleation layer that prevents the peeling of the selenium film during annealing. The highly (100)-oriented polycrystalline selenium film is grown by employing a thin tellurium (Te) nucleation layer with high-quality crystallinity. The device exhibits high external quantum efficiency in the visible region and extremely low dark current that is below 100 pA/cm2 at a reverse-bias voltage of 15 V at room temperature. The result indicates the high potential of crystalline selenium-based photodiodes to be used as photoconversion layers in imaging devices.
Effects of grain refinement on surface enhancement of thin-film chlorine-doped crystalline selenium
In this study, the surface enhancement of thin-film crystalline selenium (c-Se) is successfully demonstrated through grain refinement using chlorine (Cl) doping. We fabricated c-Se films via doping with various halogens, such as Cl, bromine (Br), and iodine (I). In particular, for Cl, we prepared c-Se films with different doping concentrations of 0, 50, and 500 ppm on glass substrates to investigate the details of concentration effects on surface enhancement. The long helical chains of Se atoms that comprise a large molecule in hexagonal Se, which is the most stable form of Se, are terminated via halogen doping into Se, leading to a marked reduction in the size of polycrystalline grains. In addition, the grain size of c-Se sharply decreases as the Cl doping concentration is increased. The mean surface roughness of a 500-ppm-Cl-doped c-Se film measured via atomic force microscopy decreased to approximately one-fourth that of the equivalent undoped c-Se film. This is a promising technology that could bring great benefits to c-Se-based imaging devices.
Hispanic marketing : connecting with the new latino consumer
* Cultural Marketing: A new understanding * The Composition of the Hispanic/Latino market * The Latino Essense of "Hispanic" * Language Considerations in Marketing to US Hispanics * Enculturation, Acculturation, and Assimilation: A Bicultural Horizon * Latino Subjective Culture: Insights for Positioning * Culturally Informed Research among Latinos * The U.S. Hispanic Marketing Industry * The Digital World of U.S. Latinos * Latino Consumers and the Future of U.S. Marketing