SciTech Connect

Title: GaAsSb-based heterojunction tunnel diodes for tandem solar cell interconnects

GaAsSb-based heterojunction tunnel diodes for tandem solar cell interconnects 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.
Authors: ; ; ;
Publication Date:
OSTI Identifier:OSTI ID: 10107906
Report Number(s):SAND--94-1597C; CONF-941203--13
ON: DE95004779; TRN: 95:001224
DOE Contract Number:AC04-94AL85000
Resource Type:Conference
Resource Relation:Conference: 1. world conference on photovoltaic energy conversion,Waikoloa, HI (United States),5-9 Dec 1994; Other Information: PBD: [1995]
Research Org:Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org:USDOE, Washington, DC (United States)
Country of Publication:United States
Language:English
Subject: 14 SOLAR ENERGY; GALLIUM ARSENIDE SOLAR CELLS; FABRICATION; EFFICIENCY 140501; PHOTOVOLTAIC CONVERSION