Multi-junction solar cell with dilute nitride sub-cell having graded doping

US9214580B2 · kind B2 · utility

Assignee

• SOLAR JUNCTION CORPORATION · US

Inventors

• Pranob Misra · Santa Clara, US
• Rebecca Elizabeth Jones · Mountain View, US
• Ting Liu · Rongcheng District, CN
• Ilya Fushman · Palo Alto, US
• Homan B. Yuen · Sunnyvale, US

Key dates

• Filing date: Oct 28, 2010
• Grant date: Dec 15, 2015
• Expiry date: Aug 23, 2031

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E10/544

Abstract

A lattice-matched solar cell having a dilute nitride-based sub-cell has exponential doping to thereby control current-carrying capacity of the solar cell. Specifically a solar cell with at least one dilute nitride sub-cell that has a variably doped base or emitter is disclosed. In one embodiment, a lattice matched multi junction solar cell has an upper sub-cell, a middle sub-cell and a lower dilute nitride sub-cell, the lower dilute nitride sub-cell having doping in the base and/or the emitter that is at least partially exponentially doped so as to improve its solar cell performance characteristics. In construction, the dilute nitride sub-cell may have the lowest bandgap and be lattice matched to a substrate, the middle cell typically has a higher bandgap than the dilute nitride sub-cell while it is lattice matched to the dilute nitride sub-cell. The upper sub-cell typically has the highest bandgap and is lattice matched to the adjacent sub-cell. In further embodiments, a multi junction solar cell according to the invention may comprise four, five or more sub-cells in which the one or more sub-cells may each comprise exponentially doped dilute nitride alloys.