Crystalline, polycrystalline and amorphous semiconductors are used to get photovoltaic effect.
The most common and effective ones under a rate of photoelectric conversion are based on silicon and gallium arsenide.
This project proposes to use an absolutely new material for this purpose – nanostructural doped diamond-like film (DLF).
The main advantage of the proposed technology is an increase of power density and reduction of production cost of the batteries.
Motivation for proposal.
DLF may be doped with different impurities. At the same time there is a strong dependence of electrical resistance rate of the film on the doping level (Figure 1).
Due to its nanostructure (short-range order is about 30 nm), DLF as distinct from diamond monocrystals and polycrystals, films in the growth process can be doped with such large atoms like: Cr, W, Mo, etc.
Depending on the nature of impurity, for example, chromium and wolframium used in DLF can create hole and electron conductivity.
But the most important is that depending on the level of doping with the same impurity, specific resistance of DLF changes more than ten orders, besides, the conduction mechanism changes greatly from the “metallic” with a positive and a very low value of temperature coefficient of resistance (TCR) – (10-5 – 10-6). K-1 up to “semiconductor” one with a very high negative value of TCR up to 10-2 K-1. It means that TCR can be changed in a given manner in the same material due to doping 8 orders more (100 million times). Fig.2.
Thus, it is possible to receive DLF with previously set properties with different types of conductivity. There can be created pseudo-large-gap structures (p-n-transitions) allowing to absorb radiation in a wide range of values and to induce electromotive force.
The second direction – is the creation of transitional structures with well-known semiconductors (Si, Ge, GaAs, ternary compound), adjusting to their specific resistivity, TCR and conductivity type.
The third direction is the creation of thin transparent and semitransparent DLF-protective films in the infrared and visible regions, and possibly, with a wider range of spectrum.
Cost estimate of the offer.
Getting DLF – is a thin-film vacuum technology, one of the cheapest technologies in electronics.
More than 1200 cm2 of DLF can be grown on one unit of the existing equipment within 60-90 min. The whole process takes 3-4 hours.
Process cost is about 200 US dollars.
Explanation to the figure 1.
The figure shows the dependence of DLF sheet resistance of the doping level (using the example of chromium). Magnetron current in this case is proportional to the level of doping under other conditions being equal, i.e. rate of reagent leakage, cathode current, arc current remain unchanged.
Explanation to the figure 2.
Figure 2 shows the dependence of the coefficient of thermal resistance (CTR) of DLF sheet resistance, in particular, of the doping level, chromium in this case.
The thickness of DLF is 1.0 – 1.2 (um)
Films produced with sheet resistance up to 1000 O / kW are used to produce small-sized high-power non-inductive resistors up to 500 W.
For solar butteries it is advisable to use DLF with high CTR, i.e. with sheet resistance of more than 10 4 O / kW.
(specific resistance is more than 1 O cm)
If you are interested – we will provide additional information and designer’s supervision over implementation of the technology.
p.s. We expect proposals for mutually beneficial cooperation