The electronic structure of Li₂B₄O₇(110) and Li₂B₄O₇(100)

Abstract

The band structure of Li2B4O7(100) and Li2B4O7(110) was experimentally determined using a combination of angle-resolved photoemission and angle-resolved inverse photoemission spectroscopies. The experimental band gap depends on crystallographic direction but exceeds 8.8 eV, while the bulk band gap is believed to be in the vicinity of 9.8 eV, in qualitative agreement with expectations. The occupied bulk band structure indicates relatively large values for the hole mass; with the hole mass as significantly larger than that of the electron mass derived from the unoccupied band structure. The Li2B4O7(110) surface is characterized by a very light mass image potential state and a surface state that falls within the band gap of the projected bulk band structure.

Effect of gadolinium doping on the electronic band structure of europium oxide

“…Combined ultraviolet photoemission (UPS) and inverse photoemission (IPES) spectroscopies were carried out, as has been done elsewhere for both main group element compound semiconductors [19][20][21] and other rare-earth oxides. 22 Some UPS and IPES spectra were taken in a single ultrahigh vacuum chamber to study the placement of both occupied and unoccupied states under the same conditions.…”

“…The IPES spectra were obtained using variable kinetic-energy incident electrons while detecting the emitted photons at a fixed energy (9.7 eV) with a Geiger-Müller detector. [19][20][21][22][23][24] The IPES resolution was limited by an instrumental linewidth of ∼400 meV, as described elsewhere. 23,24 The angle-resolved photoemission spectroscopy (ARPES) measurements employed plane-polarized synchrotron radiation dispersed by a 3-m toroidal grating monochromator 25,26 at the Center for Advanced Microstructures and Devices (CAMD).…”

“…For the undoped EuO the spectra were acquired at elevated temperatures (∼400 K) to suppress residual charging, as is common in the study of dielectric oxide materials of any appreciable thin-film thickness. [19][20][21] Segregation and formation of a "surface" Gd 2 O 3 layer at the surface of the Gd-doped EuO films can be excluded as the combined photoemission and inverse photoemission are inconsistent with such an insulating (almost certainly n-type) surface oxide. 33 …”

“…4. As long as the film is sufficiently crystalline, the ARPES measurements can be used to resolve the spectral intensity by the wave vector component normal to the surface k ⊥ , which can be found as 20,21,33,35,58,59 …”

Li2B4O7:Mn for dosimetry applications: traps and mechanisms

“…The electronic structure of Li 2 B 4 O 7 has been also studied extensively, the previous calculations being refined and verified experimentally [6][7][8][9][10]. These studies elucidated the structure of energetic bands.…”