DX Center Energy Level in InxAl1−xAs Compounds

1999 ◽  
Vol 573 ◽  
Author(s):  
Hüseyin Sari ◽  
Harry H. wieder
Keyword(s):  
Energy Level ◽  
Conduction Band ◽  
Canonical Ensemble ◽  
Grand Canonical Ensemble ◽  
Persistent Photoconductivity ◽  
Dx Centers ◽  
Indium Concentration ◽  
Self Consistent ◽  
Dx Center ◽  
Grand Canonical

ABSTRACTThe presence of DX centers in InxAl1−xAs, primarily in the indirect portion of the InxAl1−xAs bandgap, has been determined using modulation doped InxAl1−xAs/InyGa1−yAs heterostructures by means of persistent photoconductivity (PPC) and galvanomagnetic measurements. From the cooling bias experiment, the PPC, and self consistent Poisson and Schrddinger simulations the ratio of the ionized shallow donors to the DX centers is obtained. Using this ratio in the grand canonical ensemble (GCE) the energy level of DX centers is determined. It is found that the DX energy level merges with the conduction band at x ≅ 0.42 and is resonant with the conduction band in higher indium concentration.

scholarly journals A Photocapture Test of DX-Center Models

1989 ◽  
Vol 163 ◽  
Author(s):  
Harold P. Hjalmarson ◽  
S. R. Kurtz ◽  
T. M. Brennan
Keyword(s):  
Conduction Band ◽  
Cross Section ◽  
Threshold Energy ◽  
Photoionization Cross Section ◽  
Persistent Photoconductivity ◽  
Dx Centers ◽  
Null Result ◽  
Dx Center

AbstractThe DX-center model is widely used to explain data for the persistent photoconductivity (PPC) effect. An analysis of the DX-center model suggests a new experiment to test its correctness. In this experiment, photons near the threshold energy of the photoionization cross-section for the DX-center induce transitions from the partially occupied conduction band to empty DX-centers. This mechanism, which we call photocapture, competes with the usual photoionization which empties the DX-centers. The photocapture cross-section is estimated and an experimental attempt is made to detect photocapture. The significance of the null result is discussed.

DX Centers in GaAs and AlxGal-x.As: Properties and Influence on Material and Device Characteristics

1987 ◽  
Vol 104 ◽  
Author(s):  
P. M. Mooney
Keyword(s):  
Low Temperature ◽  
Carrier Concentration ◽  
Conduction Band ◽  
Energy State ◽  
Free Carrier ◽  
Free Carrier Concentration ◽  
Persistent Photoconductivity ◽  
Dx Centers ◽  
Compensation Mechanisms ◽  
Dx Center

ABSTRACTThe DX center, the lowest energy state of the donor in AlGaAs with x > 0.22, is responsible for the reduced conductivity as well as the persistent photoconductivity observed in this material at low temperature. Extensive studies of the properties of this level and of its effects on the characteristics of some heterojunction devices are reviewed here. Recent measurements are presented showing that the characteristics of the DX center remain essentially unchanged when it is resonant with the conduction band (x < 0.22) and that, independent of other compensation mechanisms, the DX center therefore limits the free carrier concentration in GaAs to a maximum of about 2×1019 cm− 3.

scholarly journals Phase diagram of brittle fracture in the semi-grand-canonical ensemble

2021 ◽  
Vol 103 (1) ◽  
Author(s):  
T. Mulla ◽  
S. Moeini ◽  
K. Ioannidou ◽  
R. J.-M. Pellenq ◽  
F.-J. Ulm
Keyword(s):  
Phase Diagram ◽  
Brittle Fracture ◽  
Canonical Ensemble ◽  
Grand Canonical Ensemble ◽  
Grand Canonical
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