Paper SS-TuP17
Electrical, Physical, and Chemical Properties of the Metal to Amorphous Hydrogenated Boron Carbide Interface

Tuesday, November 1, 2011, 6:00 pm, Room East Exhibit Hall

Boron carbide (BC), as a semiconducting material, has been under scrutiny for several decades for its use in heterostructure devices toward applications in solid-state neutron detection and thermoelectric energy conversion. The heterostructure devices are typically heterojunctions in which p-type amorphous hydrogenated boron carbide (a-B₅C:H_x) is deposited onto n-type Si, and a Cr/Au contact is applied at the a-B₅C:H_x surface. Traditionally it has been believed that Cr forms an ohmic contact at the a-B₅C:H_x interface and that the heterostructure current–voltage rectification is a classical function of the p-n junction. However, we have found through photoemission studies of Cr overlayers on a-B₅C:H_x that a complex series of interfaces is formed, involving various oxides and borides, which are likely convoluting—and could be dominating—the observed rectification. To follow up the Cr findings, we have explored Al, Cu, Au, Ag, and Ti using the same set of studies. This talk will provide an overview of the electronic, physical, and chemical interfaces between the above metals and a-B₅C:H_x in the context of understanding the I(V) characteristics of the presumed p-n junction.