Direct-band-gap Ga(NAsP)-material system pseudomorphically grown on GaP substrate

2006 ◽  
Vol 88 (18) ◽  
pp. 182108 ◽  
Author(s):  
B. Kunert ◽  
K. Volz ◽  
J. Koch ◽  
W. Stolz
Keyword(s):  
Band Gap ◽  
Material System ◽  
Direct Band Gap ◽  
Direct Band

Preparation and Characterization of Cu2Zn(GexSn1-x)Se4 Thin-films from Sputtered Elemental Precursors

2014 ◽  
Vol 1670 ◽  
Author(s):  
Antony Jan ◽  
Yesheng Yee ◽  
Bruce M. Clemens
Keyword(s):  
Band Gap ◽  
Low Cost ◽  
Solar Spectrum ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Material System ◽  
Direct Band Gap ◽  
Glass Substrates ◽  
Before And After ◽  
Direct Band

ABSTRACTThin-film absorber layers for photovoltaics have attracted much attention for their potential for low cost per unit power generation, due both to reduced material consumption and to higher tolerance for defects such as grain boundaries. Cu2ZnGeSe4 (CZGSe) comprises one such material system which has a near-optimal direct band gap of 1.6 eV for absorption of the solar spectrum, and is made primarily from earth-abundant elements.CZGSe metallic precursor films were sputtered from Cu, Zn, and Ge onto Mo-coated soda lime glass substrates. These were then selenized in a two-zone close-space sublimation furnace using elemental Se as the source, with temperatures in the range of 400 to 500 C, and at a variety of background pressures. Films approximately 1-1.5 µm thick were obtained with the expected stannite crystal structure.Next, Cu2ZnSnSe4 (CZTSe), which has a direct band gap of 1.0 eV, was prepared in a similar manner and combined with CZGSe as either compositionally homogeneous or layered absorbers. The compositional uniformity of selenide absorbers made by selenizing compositionally homogeneous Cu-Zn-Ge-Sn precursor layers was determined and the band gap as a function of composition was investigated in order to demonstrate that the band gap is tuneable for a range of compositions. For layered Cu-Zn-Ge/Cu-Zn-Sn precursor films, the composition profile was measured before and after selenization to assess the stability of the layered structure, and its applicability for forming a band-gap-graded device for improved current collection.

Optical Studies of Poly (N-Carbazole) (PVK) Blending with Polyvinylpyrrolidone (PVP) Using Tauc/Davis-Mott Model

2013 ◽  
Vol 652-654 ◽  
pp. 527-531 ◽  
Author(s):  
A.N. Alias ◽  
T.I. Tunku Kudin ◽  
Z.M. Zabidi ◽  
M.K. Harun ◽  
Ab Malik Marwan Ali ◽  
...  
Keyword(s):  
Band Gap ◽  
Urbach Energy ◽  
Quartz Substrate ◽  
Optical Studies ◽  
Direct Band Gap ◽  
Mott Model ◽  
Blended Polymer ◽  
Electronic Parameters ◽  
Direct Band ◽  
Indirect Band Gap

The optical absorption spectra of blended poly (N-carbazole) (PVK) with polyvinylpyrrolidone (PVP) in various compositions are investigated. A doctor blade technique was used to coat the blended polymer on a quartz substrate. The electronic parameters such as absorption edge (Ee), allowed direct band gap (Ed), allowed indirect band gap (Ei), Urbach edge (Eu) and steepness parameter (γ) were calculated using Tauc/Davis-Mott Model. The results reveal that the Ee, Ed and Ei increase with increasing of PVP ratio. There also have variation changing in Urbach energy and steepness parameter.

Theoretical Derivations of a Direct Band Gap Semiconductor of SiC Doped with Ge

2014 ◽  
Vol 44 (1) ◽  
pp. 167-176 ◽  
Author(s):  
Adit Ghosh ◽  
Chandrika Varadachari
Keyword(s):  
Band Gap ◽  
Direct Band Gap ◽  
Direct Band

Atomically Thin Arsenene and Antimonene: Semimetal-Semiconductor and Indirect-Direct Band-Gap Transitions

2015 ◽  
Vol 54 (10) ◽  
pp. 3112-3115 ◽  
Author(s):  
Shengli Zhang ◽  
Zhong Yan ◽  
Yafei Li ◽  
Zhongfang Chen ◽  
Haibo Zeng
Keyword(s):  
Band Gap ◽  
Direct Band Gap ◽  
Direct Band

Strain-induced semimetal-to-semiconductor transition and indirect-to-direct band gap transition in monolayer 1T-TiS2

RSC Advances ◽  
2015 ◽  
Vol 5 (102) ◽  
pp. 83876-83879 ◽  
Author(s):  
Chengyong Xu ◽  
Paul A. Brown ◽  
Kevin L. Shuford
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Plane Strain ◽  
Material Properties ◽  
First Principles ◽  
Tensile Strain ◽  
First Principles Calculations ◽  
Direct Band Gap ◽  
Direct Band ◽  
Uniform Plane

We have investigated the effect of uniform plane strain on the electronic properties of monolayer 1T-TiS2using first-principles calculations. With the appropriate tensile strain, the material properties can be transformed from a semimetal to a direct band gap semiconductor.

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