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[en] Silicon technology state of the art for single crystalline was given to be limited to less than 20% efficiency. A proposed new form of photovoltaic solar cell of high current high efficiency with double sided structures has been given. The new forms could be n⁺⁺pn⁺⁺ or p⁺⁺np⁺⁺ double side junctions. The idea of double sided devices could be understood as two solar cells connected back-to-back in parallel electrical connection, in which the current is doubled if the cell is illuminated from both sides by a V-shaped reflector. The cell is mounted to the reflector such that each face is inclined at an angle of 45 deg. C to each side of the reflector. The advantages of the new structure are: a) High power devices. b) Easy to fabricate. c) The cells are used vertically instead of horizontal use of regular solar cell which require large area to install. This is very important in power stations and especially for satellite installation. If the proposal is made real and proved to be experimentally feasible, it would be a new era for photovoltaic solar cells since the proposal has already been extended to even higher currents. The suggested structures could be stated as: n⁺⁺pn⁺⁺Vp⁺⁺np⁺⁺;n⁺⁺pn⁺⁺Vn⁺⁺pn⁺⁺ORp⁺⁺np⁺⁺Vp⁺⁺np⁺⁺. These types of structures are formed in wedged shape to employ indirect illumination by either parabolic; conic or V-shaped reflectors. The advantages of these new forms are low cost; high power; less in size and space; self concentrating; ... etc. These proposals if it happens to find their ways to be achieved experimentally, I think they will offer a short path to commercial market and would have an incredible impact on solar cell technology and applications. (author). 12 refs, 5 figs

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[en] A review of the silicon technology state of the art is given. It had been found that single crystal silicon efficiency was limitd to ≥ 20%. The reason was identified to be due to the recombination current loss mechanisms. However, use of new technologies such as back-surface field, surface passivation, double anti-reflection coatings and back-surface illumination demonstrated to achieve higher efficiencies. Experiments were carried out to evaluate the effect of back surfaces illumination on the cell efficiency enhancement. It was found that for single cell, back-surface illumination contribute a 12% increase in efficiency whereas for double cell illumination (back-to-back cells) the improvement was 59% increase in efficiency. A V-shaped flat mirror reflector with optimum angle of 45 deg. to the plane of the cell from both sides achieved the ultimate efficiency performance. Finally, a proposed high current - high efficiency solar cell called ''Double Drift'' - Double Sided Illumination Cell'' was presented. The new structures were in the form of n⁺pn⁺ or p⁺np⁺ double junctions. The expected efficiency ranges 50-60% with proper material design, double anti-reflection coatings and V-shaped irregular plane mirror reflector illumination. (author). 43 refs, 4 figs, 7 tabs

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[en] The importance of forming low-recombination passivated emitter regions while maintaining high bulk recombination lifetimes has been clearly established as necessary for the fabrication of high-efficiency silicon solar cells. Many different types of diffusion sources are available for performing the emitter diffusions for each dopant species. Each could affect device quality in a unique way, and each has particular attributes that determine its cost-effectiveness. In this study, the authors have compared the effects of PH₃ and POCl₃ diffusion sources on recombination lifetimes and emitter saturation currents. They have also examined the relative costs associated with each, including material, capital and safety costs. They found that while both sources can produce equivalent high-performance cells, PH₃ may have a higher yield in this regard

[en] By combining the steady-state and transient behaviors of a recently generalized analysis of the kinetics of metastable defects in good amorphous Si:h, it is shown that no treatment can remove all metastable defects. There is always a significant remnant that is proposed to be the observed built-in defects, which are then not a separate species, distinct from the metastable defects. This remnant is due to vibrational breaking of weak bonds in latent defect centers, and cannot be due to recombination of thermally excited carriers. If the stability can be improved by reducing the number of these latent defect centers, this will also reduce the density of built-in defects that control the initial efficiency. Furthermore, there are good reasons to believe that the source of these defects is extrinsic to a-Si:H, so that improvement in both properties may be achievable

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