Spectroscopic Study of Hydrogen Induced Defect in a-Ge:H

1990 ◽  
Vol 209 ◽  
Author(s):  
Shu Jin ◽  
Lothar Ley
Keyword(s):  
Electronic Structure ◽  
Spectroscopic Study ◽  
Density Gradient ◽  
Growth Condition ◽  
Photoelectron Spectroscopy ◽  
Defect Density ◽  
Total Yield ◽  
Structure Change ◽  
Amorphous Semiconductors ◽  
Hydrogenated Amorphous

ABSTRACTTotal yield photoelectron spectroscopy has been used to study the electronic structure change of UHV evaporated a-Ge subjected to posthydrogenation and various annealing cycles. We identify in R.T. hydrogenated a-Ge:H a new hydrogen induced defect at about Ev + 0.45eV, which can be healed upon 300°C annealing. This new defect accounts for the defect density gradient of hydrogenated amorphous semiconductors, spanning the range from ∼ 1018 cm−3 at the growing surface to 1018−1015 cm−3 in the bulk, depending on growth condition and time. The origin of this new defect is discussed.

The Interpretation of the Constant Photocurrent Method in Terms of Deep Defect Density of States in A-SI.H

1994 ◽  
Vol 336 ◽  
Author(s):  
Frank Siebke ◽  
Helmut Stiebig
Keyword(s):  
Electron Spin Resonance ◽  
Photoelectron Spectroscopy ◽  
Defect Density ◽  
Total Yield ◽  
Calibration Factor ◽  
Optical Transitions ◽  
Absolute Value ◽  
Spin Resonance ◽  
Pool Model

ABSTRACTThe constant photocurrent Method (CPM) is often used to measure the sub-bandgap absorption for the determination of the defect density. However, the absolute value of the derived defect density depends on the method of data analysis and the calibration factor. Normally the calibration factor is obtained from electron spin resonance (ESR) but the defect pool model gives rise to doubt whether ESR detects the same defects as CPm. Therefore, we propose combined total-yield photoelectron spectroscopy (TYPES) and CPM Measurements on n-type a-Si:H to determine the calibration factor. Furthermore, we calculate CPM spectra by extending an approach to simulate photoconductivity, taking into account the full set of optical transitions, and compare the results with standard evaluation Methods.

scholarly journals Effect of the sample work function on alkali metal dosing induced electronic structure change

2021 ◽  
pp. 147045
Author(s):  
Saegyeol Jung ◽  
Yukiaki Ishida ◽  
Minsoo Kim ◽  
Masamichi Nakajima ◽  
Shigeyuki Ishida ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Alkali Metal ◽  
Work Function ◽  
Structure Change

Is Thermal and Light-Induced Annealing of Met Astable Defects in a-Si:H Driven by Electrons?

1995 ◽  
Vol 377 ◽  
Author(s):  
Helena Gleskova ◽  
S. Wagner
Keyword(s):  
Electrical Conductivity ◽  
Light Intensity ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Free Electrons ◽  
Free Electron Density ◽  
Independent Variables ◽  
The Third ◽  
Defect Annealing ◽  
Hydrogenated Amorphous

ABSTRACTWe report results of a search for a unifying rate law for the annealing of metastable defects in hydrogenated amorphous silicon (a-Si:H). We tested the hypothesis that defect-annealing by both heating or illumination is driven by the density of free electrons. This hypothesis is formulated via the rate equation - dN/dt = A nα N f (T), where N is the defect density, t the time, A a constant, n the free electron density, and f (T) a function of temperature derived from a distribution of annealing energies. The model fits two sets of data, with light-intensity and electrical conductivity as the independent variables, reasonably well, with a ranging from 0.39 to 0.76, but not the third set, where we varied the temperature.

Electronic structure of actinide antimonides and tellurides from photoelectron spectroscopy

2004 ◽  
Vol 70 (20) ◽  
Author(s):  
T. Durakiewicz ◽  
J. J. Joyce ◽  
G. H. Lander ◽  
C. G. Olson ◽  
M. T. Butterfield ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Photoelectron Spectroscopy

Light-Induced Metastable Defects or Light-Induced Metastable H Atoms in a-Si:H Films?

1997 ◽  
Vol 467 ◽  
Author(s):  
C. Godet
Keyword(s):  
Experimental Data ◽  
Characteristic Time ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Exponential Time ◽  
Mobile Species ◽  
Hydrogenated Amorphous ◽  
Two Parameter ◽  
Metastable Defect ◽  
Trapping Sites

ABSTRACTIn hydrogenated amorphous silicon (a-Si:H) films, the increase of the metastable defect density under high-intensity illumination is usually described by an empirical two-parameter stretched-exponential time dependence (characteristic time τSE and dispersion parameter β). In this study, a clearly different (one-parameter) analytic function is obtained from a microscopic model based on the formation of metastable H (MSH) atoms in a-Si:H films. Assuming that MSH atoms are the only mobile species, only three chemical reactions are significant : MSH are produced from doubly hydrogenated (SiH HSi) configurations and trapped either at broken bonds or Si-H bonds, corresponding respectively to light-induced annealing (LIA) and light-induced creation (LIC) of defects. Competition between trapping sites results in a saturation of N(t) at a steady-state value Nss. A one-parameter fit of this analytical function to experimental data is generally good, indicating that the use of a statistical distribution of trap energies is not necessary.

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