A Study of the State Distribution in Various a-Si:H Materials by a New Capacitance Method

1987 ◽  
Vol 95 ◽  
Author(s):  
I. Balberg
Keyword(s):  
Hydrogenated Amorphous Silicon ◽  
Voltage Characteristic ◽  
Amorphous Semiconductors ◽  
Schottky Barriers ◽  
State Distribution ◽  
Capacitance Method ◽  
Capacitance Voltage ◽  
Silicon Materials ◽  
Hydrogenated Amorphous

AbstractA new method for the determination of the deep states density in amorphous semiconductors is presented. The method is based on the carriersemission- time dependence of the capacitance-voltage characteristics of Schottky barriers. The applicability of the method for the study of hydrogenated amorphous silicon materials is demonstrated. The pitfalls associated with trying to deduce the density of states from a single capacitance-voltage characteristic are also discussed.

Determination of the Mobile-Hydrogen Charge State in Hydrogenated Amorphous Silicon

2001 ◽  
Vol 664 ◽  
Author(s):  
Brent P. Nelsona ◽  
Yueqin Xu ◽  
Robert C. Reedy ◽  
Richard S. Crandall ◽  
A. Harv Mahan ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Electric Fields ◽  
Correlation Energy ◽  
Hydrogen Charge ◽  
Hydrogenated Amorphous Silicon ◽  
Mobile Hydrogen ◽  
Almost All ◽  
Hydrogenated Amorphous ◽  
Best Fit

ABSTRACTWe find that hydrogen diffuses as H+, H0, or H- in hydrogenated amorphous silicon depending on its location within the i-layer of a p-i-n device. We annealed a set of five p-i-n devices, each with a thin deuterium-doped layer at a different location in the i-layer, and observed the D-diffusion using secondary ionmass spectrometry (SIMS). When H-diffuses in a charged state, electric fields in the device strongly influence the direction and distance of diffusion. When D is incorporated into a device near the p-layer, almost all of the D-diffusion occurs as D+, and when the D is incorporated near the n-layer, most of the D-diffusion occurs as D-. We correlate the preferential direction of D-motion at given depth within the i-layer, with the local Fermi level (as calculated by solar cell simulations), to empirically determine an effective correlation energy for mobile-H electronic transitions of 0.39 ± 0.1 eV. Using this procedure, the best fit to the data produces a disorder broadening of the transition levels of ∼0.25 eV. The midpoint between the H0/+ and the H0/- transition levels is ∼0.20 ± 0.05 eV above midgap.

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