Bipolar Doping in Wide-Band-Gap Semiconductors

Oregon State University, Corvallis OR

Investigators

Abstract

This award to Oregon State University by the Solid State Materials Chemistry program in the Division of Materials Research is to support a collaborative project aimed at the synthesis and study of new wide band gap compound semiconductors that can be selectively doped either n- or p-type. Such bipolar materials are of fundamental interest in setting the foundation for a variety of new technologies including broad-spectrum solar cells, highly efficient polycrystalline inorganic light-emitting devices (ILEDs), complementary printed electronic circuits, and photocatalytic production of hydrogen from water. The fundamental scientific question is whether the valence and conduction band positions can be optimized to allow one material to be a host to either n- or p- doped carriers without excessive compensation. The basic premise is to seek materials that have two (or more) cations that are known to be reliable hosts of each of the conductivity types and combine them in a single material. This designed materials approach to realizing such bipolar behavior is expected to discover new p- and n-type semiconductors that will be useful in applications from solar cells to transparent electronics. As part of the project, the investigators will explore bulk powder materials and selected thin film systems using a range of experiments that probe structural, electrical, and optical properties of the materials and their defects. As part of this project, students will be trained in gaining experience in a broad range of synthesis and characterization techniques covering a wide spectrum of new wide band gap compound semiconductors from powders to thin films. In addition, this work will involve close collaboration between faculty, graduate students and undergraduate students in Chemistry and Physics departments. As a research extensive university, Oregon State University expects all students to participate in cutting edge research in order to contribute to the knowledge base, which in turn is to provide the basis for Ph.D. and undergraduate senior thesis dissertations. Students will learn the techniques of solid state chemistry and physics, and understand the scientific process by engaging in collaborative research, rigorous scrutiny of their work by peers and mentors, delivering accomplished presentations, and receiving mentorship and being mentors as appropriate. An outreach component of the proposed collaboration is the integration with a regional undergraduate summer research program sponsored by industry.