Effect of grain boundaries in silicon on minority‐carrier diffusion length and solar‐cell efficiency

1978 ◽  
Vol 33 (12) ◽  
pp. 1009-1011 ◽  
Author(s):  
T. Daud ◽  
K. M. Koliwad ◽  
F. G. Allen
Keyword(s):  
Solar Cell ◽  
Grain Boundaries ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion ◽  
Solar Cell Efficiency ◽  
Cell Efficiency

Minority Carrier Diffusion Length Improvement in Czochralski Silicon by Aluminum Gettering

1995 ◽  
Vol 378 ◽  
Author(s):  
Subhash M. Joshi ◽  
Ylrich M. GÖsele ◽  
Teh Y. Tan
Keyword(s):  
Solar Cell ◽  
Integrated Circuits ◽  
Minority Carrier ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion ◽  
Solar Cell Efficiency ◽  
Czochralski Silicon ◽  
Si Substrates ◽  
Cell Efficiency ◽  
Si Wafer

AbstractGettering is widely used for fabricating integrated circuits using Si substrates, and has great potential for solar cell fabrications as well. Recently available solar cell efficiency studies have shown the benefits of the wafer backside Al, attributable to effects of gettering, a wafer backside field, and passivation of grain boundaries and dislocations. In this paper, we report experimental results which showed unambiguously that Czochralski Si wafer bulk minority carrier diffusion lengths can be significantly improved due to gettering of impurities by wafer backside Al, which also provided a protection from environmental contamination.

Surface recombination effects on minority carrier diffusion length measurements using electron beam-induced current

1990 ◽  
Vol 48 (4) ◽  
pp. 744-745
Author(s):  
D.P. Malta ◽  
M.L. Timmons
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Effective Diffusion ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Logarithmic Scale ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

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