Elementary energy bands in the band structure of the narrow-band-gap semiconductor CdSb

AbstractWe report calculations which show that the band structure of CoSb3 is typical of a narrow band-gap semiconductor. The gap is strongly dependent on the relative position of the Sb atoms inside the unit cell. We obtain a band gap of 0.22 eV after minimization of these position. This value is more than four times larger than the result of a previous calculation which reported that the energy bands near the Fermi surface are unusual. The electronic states close to the Fermi level are properly described by a two-band Kane Model. The calculated effective masses and band gap are in excellent agreement with Shubnikov de Haas and Hall effect measurements. Recent measurements of the transport coefficients of this compound can be understood assuming it is a narrow band gap semiconductor, in agreement with our results.

Download Full-text

Chemical Trend in Band Structure of 3d-Transition-Metal-Doped AlN Films

Materials Science Forum ◽

10.4028/www.scientific.net/msf.924.322 ◽

2018 ◽

Vol 924 ◽

pp. 322-325 ◽

Cited By ~ 1

Author(s):

Nobuyuki Tatemizo ◽

Saki Imada ◽

Yoshio Miura ◽

Koji Nishio ◽

Toshiyuki Isshiki

Keyword(s):

Optical Absorption ◽

Band Structure ◽

Band Gap ◽

Band Gap Energy ◽

Energy Bands ◽

Additional Energy ◽

Model Calculations ◽

Lattice Constants ◽

Near Ultraviolet ◽

Metal Doped

Band structure calculations for radiofrequency-sputtered AlN-films doped with various 3d-transition-metals (TM: V, Cr, and Mn) were conducted to investigate the origin of the characteristic optical absorption structures. Experimentally evaluated crystal structures and lattice constants of the synthesized films were adopted for supercells. The model calculations showed that additional energy bands mainly consisting of 3d e and t states of TMs are formed in the band gap of AlN (6.2 eV), and that their potentials depend on the TM species. It was also shown that the Fermi levels of Cr- and Mn-doped AlN lie within the spin-up t band, while the Fermi level of V-doped AlN lies between the spin-up e and t bands. These findings imply that the materials have TM species-dependent, multiple absorption paths with lower energy than the band gap energy of AlN, resulting in optical absorption in the near-ultraviolet, visible, and infrared regions.

Download Full-text

Влияние предварительной ионной бомбардировки на формирование нанопленок Co и CoSi-=SUB=-2-=/SUB=- на поверхности Si при твердофазном осаждении

Письма в журнал технической физики ◽

10.21883/pjtf.2022.05.52152.19043 ◽

2022 ◽

Vol 48 (5) ◽

pp. 27

Author(s):

И.Х. Турапов ◽

И.Р. Бекпулатов ◽

А.К. Ташатов ◽

Б.Е. Умирзаков

Keyword(s):

Band Structure ◽

Band Gap ◽

Layer Thickness ◽

Narrow Band

In work to obtain ordered nanophases of Co and CoSi2, nuclei are preliminarily created on the Si surface by bombardment with Ar+ ions with E0 = 0.5 keV and D = 8 × 1013 cm-2. It was found that a narrow band gap (Еg = 0.3 eV) appears in the band structure at a Co layer thickness of less than 3 ML. The metallic properties of the Co film are manifested at a thickness of more than 4-5 ML. Heating the Co/Si(111) system at T = 900 K leads to the formation of nanophases and CoSi2 nanofilms. Еg of CoSi2 nanophases with Ɵ  3 ML is ~0.8 eV, and of CoSi2 films - 0.6 eV.

Download Full-text