Element-Selective Observation of Electronic Structure Transition between Semiconducting and Metallic States in Boron-Doped Diamond Using Soft X-ray Emission and Absorption Spectroscopy

Abstract

The electronic structure transition between the semiconducting and metallic states in boron (B)-doped diamonds was elementselectively observed by soft X-ray emission and absorption spectroscopy using synchrotron radiation. For lightly B-doped diamonds, the B 2p-density of states (DOS) in the valence band was enhanced with a steep-edge feature near the Fermi level, and localized acceptor levels, which are characteristic of semiconductors, were clearly observed both in B 2p-and C 2p-DOS in the conduction bands. For heavily B-doped diamonds, the localized acceptor levels developed into extended energy levels and the new energy levels generated formed an extended conduction band structure that overlapped with the valence band. Thus, the metallic energy band structure is actually formed by heavy boron doping. These valence and conduction band structures observed by soft X-ray emission and absorption spectroscopy accounted for the electrical properties of B-doped diamonds.

An etched multilayer as a dispersive element in a curved‐crystal spectrometer: implementation and performance

“…In addition, we have compared the C K emissionofgraphite and B 4 C obtained with the EM implemented in IRIS [22] and with a grating spectrometer [23] .For this last kind of spectrometer, absorption does not limit the spectral resolution,as the diffracting structures are at the surface of the grating. Then, much better resolution can be reached in the soft x-ray and extreme UV ranges.…”

“…With the MM, the C K emission band would have been observed as a broad and rather symmetrical peak [12] [14] . obtained with the EM (solid line) setup in the curved-crystal spectrometer and with a grating spectrometer [23] (dotted line).…”

Core-level electronic structure evolution of heavily boron-doped superconducting diamond studied with hard x-ray photoemission spectroscopy

“…[8][9][10] In particular, the evolution of the electronic structure to the superconducting phase, lying next to the semiconductor to metal transition, 11,12 is a field of active research. Physical properties of boron-doped diamond have been systematically studied over several years 13 using films made with microwave plasma-assisted chemical-vapor deposition ͑MPCVD͒.…”

“…Thus, experimental investigations for the bulk core-level electronic structures of C and B core levels are indeed desirable to understand the physical properties of the heavily boron-doped diamond superconductor, as well as for understanding recent x-ray absorption studies. 8,9 In the present study, we use hard x-ray photoemission spectroscopy ͑HXPES͒ at photon energies of 8 keV to study the intrinsic boron concentration dependent core-level electronic states of heavily boron-doped diamond films over a wide range: from nonsuperconducting samples to superconducting samples. Since it is known that HXPES using 8 keV photon energy can provide a photoelectron mean free path of as long as 70 Å for diamond, 16 the obtained results using hard x-ray excitation better represent the bulk electronic structure compared to experiments using conventional laboratory x rays.…”

Chemical Analysis of Impurity Boron Atoms in Diamond Using Soft X-Ray Emission Spectroscopy

“…2,3 To clarify the relationship between the electronic structure and local structure of the boron atoms in B-diamond, researchers have analyzed the valence band and conduction band by soft X-ray emission spectroscopy (XES) and absorption spectroscopy (XAS) using synchrotron radiation (SR). [4][5][6] These spectroscopic studies have elucidated that covalent B-C bond formation in a diamond matrix is important for acceptor formation in p-type B-diamond semiconductors. Additionally, superconducting characteristics have been discovered in heavily boron-doped diamond, 7 and its electronic structure has been analyzed by SR photoemission spectroscopy 8 and the X-ray scattering method.…”