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Solar Grade III-V/Si Substrate

Tandem Sun fabricates the proprietary Solar Grade III-V/Si substrates comprising  high crystalline quality III-V semiconductors on low cost Si substrates with a direct III-V/Si heterojunction (HJ) by Corrugated Epitaxial Lateral Overgrowth (CELOG) technology. The Solar Grade III-V/Si substrates can eventually be the alternatives to the conventional III-V substrates in the industry of photovoltaics, photonic integrated circuits (PICs), optical interconnects, and integrated circuits (ICs) beyond CMOS because of their low cost, scalable wafer size (up to 12 inch) and unique synergetic electronic and optical properties arising from the direct III-V/Si heterojunctions. Recently, the Solar Grade InP/Si substrate has been used to create the InP/Si heterojunction photodiode for the first time (News).

The threading dislocation free III-V/Si heterojunctions can be realised by CELOG in a manner of Epitaxial Fusion (EF) that combines the advantages of high crystalline quality III-V semiconductors in wafer bonding and the free choice of lattice constant of III-V semiconductors in heteroepitaxy.

                        XTEM red                     XHRTEM red

 (a) Cross-sectional TEM image of threading dislocation free InP on Si grown by CELOG and (b) high resolution XTEM image of CELOG InP/Si direct heterojunction formed in a manner of Epitaxial Fusion (EF). (Presented at EUPVSEC 2016, Munich, Germany)

Si based multi-junction solar cell (SiMJSC)

The technology behind Tandem Sun is the most efficient solar harvesting technology of today. It is based on the concept of multi layered PV solar cells making use of a larger part of the solar spectrum than conventional crystalline Si and thin film cells. The new technology increases efficiency and reduces cost of PV solar cells at the same time. The technology is patented.


SiMJSC Si based multijunction solar cell

The core value of Tandem Sun can be divided into four components:

1. Higher efficiency.
2. Low cost.
3. Correlates with common production methods.
4. Based on easy accessible and abundant silicon.


Tandem Sun develops and markets SiMJSC enabled by the Solar Grade III-V substrate technology, and licenses the proprietary technology. Please contact us for further inquiries.

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