High efficiency cell development. Final technical progress report, 1978. Texas Instruments report No. 03-79-16. [Tandem Junction Cell with back contacts]

Technical Report · Thu Feb 01 04:00:00 EST 1979

DOI:https://doi.org/10.2172/5868308· OSTI ID:5868308

Carbajal, Bernard G.

This activity focused on the development of a novel cell structure, the Tandem Junction Cell (TJC), developed at Texas Instruments. The TJC features an all back contact cell having a textured front surface that contains an electrically floating N/sup +//P junction. The illuminated side (front) of the TJC is textured to reduce reflection and to increase the path length of the absorbed light. A shallow N/sup +/ junction is diffused into the front surface. The thin base region, approx. 100 ..mu..m, is P type. The N/sup +/ collecting junction and P/sup +/ contact regions are formed on the back side. The N/sup +/ and P/sup +/ regions are in the form of an interposed finger pattern. This solar cell structure has several very attractive built-in features. With no contact metallization on the front side, shadowing is eliminated. The back contact system is particularly useful in module assembly. All interconnects and bus bars can be located behind the solar cells and virtually no module space is wasted. The TJC appears to offer the opportunity to achieve very high efficiency for silicon solar cells. Development work under this activity was primarily focused on improvements in the contact metallization pattern, shallow front N/sup +/ diffusion and methods to improve V/sub oc/. Included in this effort, is the effect of minority carrier lifetime and cell thickness. At the beginning of this program, 2 x 2 cm TJC's with AM1 efficiency in the 10 to 12% range had been fabricated.

• Research Organization: Texas Instruments, Inc., Dallas (USA)
• DOE Contract Number: NAS-7-100-954881
• OSTI ID: 5868308
• Report Number(s): DOE/JPL/954881-5
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
CARRIER LIFETIME
CRYSTALS
DESIGN
DIFFUSION
DIMENSIONS
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRIC CONDUCTIVITY
ELECTRIC CONTACTS
ELECTRIC POTENTIAL
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
EQUIPMENT
FABRICATION
FILL FACTORS
JUNCTIONS
LIFETIME
MONOCRYSTALS
P-N JUNCTIONS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
SEMICONDUCTOR JUNCTIONS
SILICON SOLAR CELLS
SOLAR CELLS
SPECTRAL RESPONSE
THICKNESS