GaAsSb-based heterojunction tunnel diodes for tandem solar cell interconnects

Conference · Sun Jan 01 04:00:00 EST 1995

OSTI ID:10107906

Zolper, J C; Klem, J F; Plut, T A; Tigges, C P

We report a new approach to tunnel junctions that employs a pseudomorphic GaAsSb layer to obtain a band alignment at a InGaAs or InAlAs p-n junction favorable for forward bias tunneling. Since the majority of the band offset between GaAsSb and InGaAs or InAlAs is in the valence band, when an GaAsSb layer is placed at an InGaAs or InAlAs p-n junction the tunneling distance is reduced and the tunneling current is increased. For all doping levels studied, the presence of the GaAsSb-layer enhanced the forward tunneling characteristics. In fact, in a InGaAs/GaAsSb tunnel diode a peak tunneling current sufficient for a 1000 sun intercell interconnect was achieved with p = 1.5{times}l0{sup 18} cm{sup -3} while a similarly doped all-InGaAs diode was rectifying. This approach affords a new degree of freedom in designing tunnel junctions for tandem solar cell interconnects. Previously only doping levels could be varied to control the tunneling properties. Our approach relaxes the doping requirements by employing a GaAsSb-based heterojunction.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 10107906
• Report Number(s): SAND--94-1597C; CONF-941203--13; ON: DE95004779
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501
EFFICIENCY
FABRICATION
GALLIUM ARSENIDE SOLAR CELLS
PHOTOVOLTAIC CONVERSION