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Demonstration of a nipi ‐diode photovoltaic
Author(s) -
Cress Cory D.,
Polly Stephen J.,
Hubbard Seth M.,
Raffaelle Ryne P.,
Walters Robert J.
Publication year - 2011
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.1071
Subject(s) - optoelectronics , materials science , solar cell , equivalent series resistance , diode , doping , semiconductor , quantum well , photovoltaic system , open circuit voltage , short circuit , photolithography , voltage , electrical engineering , optics , laser , physics , engineering
Abstract The simulation, growth, processing, and characterization of a three‐period GaAs n‐type/intrinsic/p‐type/intrinsic … ( nipi ) doping solar cell is demonstrated. A V‐groove etching process is characterized and used to expose the multiple n‐type and p‐type layers for electrical connection made by interdigitated grid‐finger electrodes. A five‐layer photolithographic process flow is developed and used to make 1 × 1 cm 2 devices with varying grid‐finger separation. Device simulations of the structure indicate that strong rectification can be achieved in the parallel‐connected three period nipi GaAs solar cell structure provided the necessary semiconductor doping compensation is achieved in the region near the metal‐semiconductor interfaces. Experimentally, the improvements observed in the open circuit voltage, short circuit current, and ideality of the devices following thermal annealing suggests the formation of barriers near the contacts, which support the simulation results. A comparison of the short circuit current and series resistance under illumination indicate a tradeoff between shadowing and series resistance, which may be overcome with modification to the device structure. Ultimately, these results show promise towards the development of high efficiency solar cells or radioisotope batteries, and offer a novel device structure for the incorporation of nano‐structures such as quantum wells or quantum dots. Copyright © 2010 John Wiley & Sons, Ltd.