Formation Energy of Intrinsic Point Defects in Si and Ge and Implications for Ge Crystal Growth

2013 ◽  
Vol 2 (3) ◽  
pp. P104-P109 ◽  
Author(s):  
Eiji Kamiyama ◽  
Koji Sueoka ◽  
Jan Vanhellemont
Keyword(s):  
Crystal Growth ◽  
Point Defects ◽  
Formation Energy ◽  
Intrinsic Point Defects

scholarly journals First-Principles Assessment of the Structure and Stability of 15 Intrinsic Point Defects in Zinc-Blende Indium Arsenide

Crystals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 48 ◽  
Author(s):  
Qing Peng ◽  
Nanjun Chen ◽  
Danhong Huang ◽  
Eric Heller ◽  
David Cardimona ◽  
...  
Keyword(s):  
Fermi Level ◽  
Charge State ◽  
Indium Arsenide ◽  
Point Defects ◽  
First Principles ◽  
Formation Energy ◽  
Fast Diffusion ◽  
Intrinsic Point Defects ◽  
Zinc Blende ◽  
Tetrahedral Sites

Point defects are inevitable, at least due to thermodynamics, and essential for engineering semiconductors. Herein, we investigate the formation and electronic structures of fifteen different kinds of intrinsic point defects of zinc blende indium arsenide (zb-InAs ) using first-principles calculations. For As-rich environment, substitutional point defects are the primary intrinsic point defects in zb-InAs until the n-type doping region with Fermi level above 0.32 eV is reached, where the dominant intrinsic point defects are changed to In vacancies. For In-rich environment, In tetrahedral interstitial has the lowest formation energy till n-type doped region with Fermi level 0.24 eV where substitutional point defects In A s take over. The dumbbell interstitials prefer < 110 > configurations. For tetrahedral interstitials, In atoms prefer 4-As tetrahedral site for both As-rich and In-rich environments until the Fermi level goes above 0.26 eV in n-type doped region, where In atoms acquire the same formation energy at both tetrahedral sites and the same charge state. This implies a fast diffusion along the t − T − t path among the tetrahedral sites for In atoms. The In vacancies V I n decrease quickly and monotonically with increasing Fermi level and has a q = − 3 e charge state at the same time. The most popular vacancy-type defect is V I n in an As-rich environment, but switches to V A s in an In-rich environment at light p-doped region when Fermi level below 0.2 eV. This study sheds light on the relative stabilities of these intrinsic point defects, their concentrations and possible diffusions, which is expected useful in defect-engineering zb-InAs based semiconductors, as well as the material design for radiation-tolerant electronics.

Effect of intrinsic point defects on ZnO electronic structure and absorption spectra

2020 ◽  
Vol 34 (17) ◽  
pp. 2050147
Author(s):  
Yuqin Guan ◽  
Qingyu Hou ◽  
Danyang Xia
Keyword(s):  
Absorption Spectrum ◽  
Electronic Structure ◽  
Band Gap ◽  
Absorption Spectra ◽  
Point Defects ◽  
Formation Energy ◽  
Stable Structure ◽  
Impurity Level ◽  
Intrinsic Point Defects ◽  
Rich Condition

The effect of intrinsic point defects on the electronic structure and absorption spectra of ZnO was investigated by first-principle calculation. Among the intrinsic point defects in ZnO, oxygen vacancies [Formula: see text] and interstitial zinc [Formula: see text] have the lower formation energy and the more stable structure under zinc(Zn)-rich condition, whereas zinc vacancies [Formula: see text] and interstitial oxygen [Formula: see text] have the lower formation energy and the more stable structure under oxygen(O)-rich condition. The band gap of [Formula: see text] becomes narrow and the absorption spectrum has a redshift. In the visible region, the photo-excited electron transition of [Formula: see text] is graded from the valence band top to the impurity level and then to the conduction band bottom, showing the redshift of absorption spectrum of [Formula: see text] and explaining the reason of [Formula: see text] forming a deep impurity levels in ZnO. Moreover, the impurity energy level of [Formula: see text] coincides with the Fermi level, indicating the significant trap effect and the slow recombination of electrons and holes, which are conducive to the design and preparation of novel ZnO photocatalysts. The band gap of [Formula: see text] and [Formula: see text] broadened and the absorption spectrum showed blueshift, explaining the different values of the ZnO band gap width.

Intrinsic Point Defects in Silicon Crystal Growth

2011 ◽  
Vol 178-179 ◽  
pp. 3-14 ◽  
Author(s):  
Vladimir V. Voronkov ◽  
Robert Falster
Keyword(s):  
Crystal Growth ◽  
Point Defects ◽  
Vacancy Concentration ◽  
Silicon Crystal ◽  
Growth Conditions ◽  
Intrinsic Point Defects ◽  
Silicon Crystals ◽  
Low Concentrations ◽  
Different Populations ◽  
Vacancy Concentrations

In dislocation-free silicon, intrinsic point defects – either vacancies or self-interstitials, depending on the growth conditions - are incorporated into a growing crystal. Their incorporated concentration is relatively low (normally, less than 1014 cm-3 - much lower than the concentration of impurities). In spite of this, they play a crucial role in the control of the structural properties of silicon materials. Modern silicon crystals are grown mostly in the vacancy mode and contain many vacancy-based agglomerates. At typical grown-in vacancy concentrations the dominant agglomerates are voids, while at lower vacancy concentrations there are different populations of joint vacancy-oxygen agglomerates (oxide plates). Larger plates – formed in a narrow range of vacancy concentration and accordingly residing in a narrow spatial band – are responsible for the formation of stacking fault rings in oxidized wafers. Using advanced crystal growth techniques, whole crystals can be grown at such low concentrations of vacancies or self-interstitials such that they can be considered as perfect.

The Formation of Defects Degrading Gate Oxide Integrity During CZ-Si Crystal Growth

1995 ◽  
Vol 378 ◽  
Author(s):  
Y. Tsumori ◽  
K. Nakai ◽  
T. Iwasaki ◽  
H. Haga ◽  
K. Kojima ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Point Defects ◽  
Defect Density ◽  
Gate Oxide ◽  
Cooling Time ◽  
Intrinsic Point Defects ◽  
Pair Annihilation ◽  
Temperature Ranges ◽  
Gate Oxide Integrity

AbstractThe formation of grown-in defects degrading the gate oxide integrity (GOI) has been studied. The growth-halting experiments were carried out to investigate the temperature ranges at which the formation of the defects was promoted or suppressed. GOI is improved in the crystal regions slowly cooled above 1330°C and between 1060°C and 1100°C. It is degraded in the crystal regions held below 1060°C. In the peripheral of the crystals, those temperature ranges are about 30°C lower. The defects are formed and grown below 1060°C in the center part of the crystal. The defect density is decreased with cooling time between 1060°C and 1100°C. These phenomena are considered to be closely related with reactions of intrinsic point defects, that is, the pair annihilation or the aggregation. The temperatures at which the pair annihilation and the aggregation of the point defects occur are dependent upon the supersaturation of the point defects.

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