EAPSI: Zinc oxide-silicon nanostructures for enhanced light sensors

Pradel Ken C, Atlanta GA

Investigators

Abstract

Zinc oxide is a promising semiconductor material for electronic applications due to its low cost, ease of synthesis, and unique optical properties. However, one challenge that has prevented this material from being more widely commercialized is the difficulty in controlling its electrical properties through a process known as doping. If full control of zinc oxide?s electrical properties can be achieved, it would allow for low cost light sensors or light emitting diodes. The researcher?s thesis has focused on stabilizing the doping process in zinc oxide. As a part of the EAPSI program, the researcher will be working with Dr. Naoki Fukata at the National Institute for Materials Science (NIMS) in Tsukuba, Japan to integrate zinc oxide and silicon nanostructures together for improved photodetectors. By reducing the device features to the nanoscale, the device?s sensitivity can be improved. Dr. Fukata specializes in the growth of silicon nanostructures, and has access to the facilities needed to characterize this material. Historically, doping zinc oxide to make it p-type has been challenging due to the low formation energy of compensating donor defects. If stable p-type ZnO could be realized, it would be a cheap alternative to other materials like GaN which is currently used in optoelectronics such as laser diodes and photosensors. It was found that antimony (Sb) could be used to produce low temperature, solution grown p-type ZnO nanowires with an unprecedented stability of 18 months. While the researcher has produced p-n homojunctions between n- and p-type ZnO, in order to broaden this material?s applicability, it is also worthwhile to study its interactions with other semiconductors. Working with Dr. Fukata, the researcher will grow p-type ZnO nanowires on n-type Si nanowires in order to produce a heterojunction structure. By reducing the material to high surface area nanowires, enhanced photodetectors with unique optoelectronic properties will be produced. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.