Equilibrium Between Charge Carriers, Charged Centers, and Dangling Bonds in Amorphous Silicon

1988 ◽  
Vol 118 ◽  
Author(s):  
C. Fortmann
Keyword(s):  
Amorphous Silicon ◽  
Charge Carriers ◽  
Dangling Bonds

Metastable Defects in the Amorphous Silicon-Germanium Alloys

2003 ◽  
Vol 762 ◽  
Author(s):  
J. David Cohen
Keyword(s):  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Dangling Bonds ◽  
Annealing Behavior ◽  
Fundamental Properties ◽  
Silicon Materials ◽  
Salient Features ◽  
The Individual ◽  
Amorphous Silicon Germanium ◽  
Silicon Germanium Alloys

AbstractThis paper first briefly reviews a few of the early studies that established some of the salient features of light-induced degradation in a-Si,Ge:H. In particular, I discuss the fact that both Si and Ge metastable dangling bonds are involved. I then review some of the recent studies carried out by members of my laboratory concerning the details of degradation in the low Ge fraction alloys utilizing the modulated photocurrent method to monitor the individual changes in the Si and Ge deep defects. By relating the metastable creation and annealing behavior of these two types of defects, new insights into the fundamental properties of metastable defects have been obtained for amorphous silicon materials in general. I will conclude with a brief discussion of the microscopic mechanisms that may be responsible.

scholarly journals Modeling of Beta Conductivity in Tritiated Amorphous Silicon

2000 ◽  
Vol 609 ◽  
Author(s):  
Stefan Costea ◽  
Franco Gaspari ◽  
Tome Kosteski ◽  
Stefan Zukotynski ◽  
Nazir P. Kherani ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Amorphous Silicon ◽  
Silicon Film ◽  
Radioactive Decay ◽  
Dangling Bonds ◽  
Electron Hole ◽  
Beta Particles ◽  
Amorphous Silicon Film ◽  
Recombination Centers

ABSTRACTThe change with time in the electrical conductivity of a hydrogenated-tritiated amorphous silicon film (a-Si:H:T) has been studied. The conductivity decreased with time after deposition. A model is developed to account for the decrease. The radioactive decay of tritium into helium produces energetic beta particles. Each β particle creates over 1500 electron-hole pairs in the film thereby increasing the conductivity of the film. The 3He atoms diffuse away leaving dangling bonds behind. We find that neutral dangling bonds (D0) are responsible for the decrease in conductivity by acting as recombination centers in the material.

Temperature Dependence of the Decay of Optically Excited Charge Carriers in Amorphous Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
J. Whitaker ◽  
P. C. Taylor
Keyword(s):  
Temperature Dependence ◽  
Amorphous Silicon ◽  
State Density ◽  
Charge Carriers ◽  
Band Tail ◽  
Spin Resonance ◽  
Recombination Processes ◽  
Long Time ◽  
Tail Structure ◽  
Kinetics Of

AbstractWe report the temperature dependence of the growth and decay of the optically induced electron spin resonance (LESR) on short and long time scales (10-3 s < t < 2500 s). This range of times spans the region between previously published photoluminescence and the LESR data. In addition, we examine the steady-state density of optically excited charge carriers as a function of temperature. These measurements lead to a better understanding of the band tail structure of amorphous silicon as well as the kinetics of the excitation and recombination processes.

Evidence For Trap-Conversion Induced Instability In Amorphous Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
Vikram L. Dalal ◽  
Puneet Sharma ◽  
Abdul Aziz
Keyword(s):  
Energy Range ◽  
Amorphous Silicon ◽  
Photon Energy ◽  
Correlation Energy ◽  
Early Time ◽  
Photon Energy Range ◽  
Dangling Bonds ◽  
Defect States ◽  
Conversion Model ◽  
Kinetics Of

AbstractIt has been shown recently that there are two distinct types of recovery during annealing of amorphous Silicon after degradation due to light soaking. It has been postulated that the two different kinetics of annealing point to the existence of two different types of states, with perhaps one state being charged dangling bonds and the other state being neutral dangling bonds. To see if two kinds of states exist, in this paper, we study the kinetics of degradation within the first 100 seconds, and also study the entire absorption curve at all degradation times. An analytical model is derived for early time degradation based on the conversion of a D- state into a neutral dangling band by absorption of a light generated ( the trap-to-dangling bond conversion model of Adler) and the experimental data of degradation versus light intensity fit the predictions of the model very well. The model also predicts that the Adler-type negatively charged defect states, which have a negative correlation energy, upon conversion will transform into Do states at a higher energy, and therefore, there should be a decrease in absorption corresponding to states closer to the valence band, and an increase in absorption corresponding to states near the mid-gap. For the films where such D- states are deliberately introduced by using a small oxygen (a donor atom) leak, we see strong evidence for such a behavior in absorption, with a decrease in the 1.3-1.4 eV photon energy range, and an increase in the 1.1 eV photon energy range. The increase in Do corresponds well with the decrease in photo-conductivity, even at the earliest times.

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