title: Direct visualization of the N impurity state in dilute GaNAs using scanning tunneling microscopy.
abstract: The interaction between nitrogen (N) impurity states in III-V compounds plays a key role in controlling optoelectronic properties of the host materials. Here, we use scanning tunneling microscopy to characterize the spatial distribution and electronic properties of N impurity states in dilute GaNAs. We demonstrated that the N impurity states can be directly visualized by taking empty state current images using the multipass scanning method. The N impurity states broadened over several nanometers and exhibited a highly anisotropic distribution with a bowtie-like shape on the GaAs(110) surface, which can be explained by anisotropic propagation of strain along the zigzag chains of Ga and As atoms in the {110} plane. Our experimental findings provide strong insights into a possible role of N impurity states in modifying properties of the host materials.
authors.affiliation: National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan. ishida.nobuyuki@nims.go.jp.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Ishida
authors.forename: Masafumi
authors.initials: M
authors.lastname: Jo
authors.forename: Takaaki
authors.initials: T
authors.lastname: Mano
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sakuma
authors.forename: Takeshi
authors.initials: T
authors.lastname: Noda
authors.forename: Daisuke
authors.initials: D
authors.lastname: Fujita