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GT Advanced Technologies' (NASDAQ:GTAT) epitaxial growth on thin lamina patent was published on 2/6/14. Epitaxy is defined as the growth of a thin layer on the surface of a crystal so that the layer of growth has the same structure as the underlying crystal. GT's patent essentially enables the growth of a semiconductor material on a donor body, by firing GT's Hyperion's ion cannon which splits (exfoliates) the semiconductor material from the donor body, to form a super thin lamina (layer) of the semiconductor material. The resulting lamina from the first process can be exfoliated by Hyperion a second time to form an additional semiconductor lamina. The patent can be applied across a broad range of semiconductor materials to epitaxally grow GaN, AlGaN, AN, Ge, Ga(In)As, GaInP, AlGaInP, AlInP, InGaN, SiC, GaAs. The epitaxial layer may be doped as either n-type or p-type while it is being grown. The donor bodies for this patent include germanium, gallium arsenide, silicon carbide, silicon and gallium nitride.

One of the most interesting findings within this patent was related to PV (photovoltaic), specifically the creation of a triple junction PV cell and the ability to incorporate the thin (PV cell) lamina into an electronic device. Not only does GT have the ability to create thin film solar cells but they also have the ability to stack the thin film solar cells to form a triple junction PV cell that is still less than 25 microns thick before it is incorporated into an electronic device all while rocking a 40%+ efficiency rating. Below are some details from the epitaxial growth on thin lamina patent.

In some embodiments a triple junction PV cell may be fabricated with lamina such as a germanium lamina

The combined thickness of the lamina and epitaxial layer may be between about 2 microns and about 25 microns such as between 15 and 25 microns. One, two or more additional layers may be formed on the either surface of the lamina/epitaxial layer assembly before incorporating the lamina into an electronic device.

A triple junction PV cell would be a solar cell made of up 3 p-n junctions made of different semiconductor materials. Each p-n junction will produce electricity in response to different wavelengths of light. The electric current is produced at multiple wavelengths which will result in a high conversion efficiency of the solar cells. The amazing part of GT's patent is just how thin the combined layers of lamina/epitaxial are, between 2 microns and 25 microns thick before they are incorporated into an electronic device. The iPhone 5s home button measures 170 microns thick. Hold up, did the patent say, before the solar cells are incorporated into an electronic device? I've been reading various feedbacks about the solar cell efficiency ratings being too low to actually charge a phone.

The combined thickness of the lamina and epitaxial layer may be between about 2 microns and about 25 microns such as between 15 and 25 microns. One, two or more additional layers may be formed on the either surface of the lamina/epitaxial layer assembly before incorporating the lamina into an electronic device.

What if I told you other companies are producing multi-junction solar cells at over 44% efficiency and that one of the companies involved already has a relationship with GT, would you believe me? Well you should, because the company that has both stacking technologies and experience with multi-junction solar cells is Soitec. GT signed an agreement with Soitec over a year ago on February 25th, 2013. A brief description of Soitec's stacking and Concentrix technology are below.

Smart Stacking

Soitec's Smart Stacking is "a wafer-to-wafer technology platform that enables very thin layers of partially or fully processed wafers to be transferred onto other wafers. It is supported by decades of substrate engineering expertise and a strong IP portfolio." The thickness of transferred layers can range from just a few microns to several hundred microns.

Concentrix Technology -

Concentrix technology uses optimized III-V-based multi-junction solar cells in which different types of solar cells are stacked on top of one another. Each cell type is designed to convert a certain range of the solar spectrum: short wave radiation, medium wave radiation and infrared. For about 20 years, multi-junction solar cells were used in space applications. The energy yield and the potential of these high-efficiency cells are enormous. In the lab, an efficiency of 44.7% has been achieved. This is almost double the efficiency of conventional solar cells.

The Obscure Analyst Takeaway:

In my most recent article GT Advanced Technologies: Is About to Enjoy Some Apple Solar Pie, I highlighted the solar cell thin film patent that GT now has under their belt. It is now clear based on reviewing the epitaxial growth on thin lamina patent, that GT is on their way to delivering a triple junction PV cell, composed of three thin film solar cell laminas, that will achieve a 40% or better efficiency rating. GT only has one major electronic device customer today and I think we know who that is, yes you got it, Apple (NASDAQ:AAPL). A single thin film of solar cells might not be efficient enough to charge a mobile phone, but a triple junction PV cell boasting an efficiency rating at or above 40%, just might just do the trick. How about them Apples?

Source: GT Advanced Technologies Is Ready To Electrify The Mobile World

Additional disclosure: I am long GTAT and have no plans to buy or sell any holdings in the next 72 hours.