Improvement of Front-Junction GaInP by Point-Defect Injection and Annealing: Preprint

Research output: Contribution to conferencePaper

Abstract

Traditional front junction GaInP solar cells are radiation tolerant and can have good diffusion length, but have limited voltage and thus efficiency. Here, we investigate the impact of annealing on GaInP device performance. First, Zn-doped GaInP/AlGaInP double heterojunction structures are studied in order to investigate the impact of annealing in a simple structure. While standard anneals lower diffusion length and lifetime, annealing after injecting point-defects improves material quality, presumably by eliminating sources of non-radiative recombination. Atomic ordering is reduced by the anneal, which raises the device bandgap and requires consideration. These results can be used to improve front junction device performance while controlling the bandgap. Then, GaInP front-junction devices are created using anneals with and without point-defect injection. Voc and EQE trends follow the diffusion length and lifetime trends from the DH structures. Baseline devices have Woc of 0.484 V, raising to 0.504 V after a high temperature anneal. However, injecting point defects prior to the anneal results in a front junction device with Woc of 0.405 V and a diffusion length greater than 8 micrometers. Optimized front-junction GaInP devices with an ARC have ~20% efficiency without a rear reflector.
Original languageAmerican English
Number of pages6
StatePublished - 2021
Event2021 IEEE 48th Photovoltaic Specialists Conference (PVSC) -
Duration: 20 Jun 202125 Jun 2021

Conference

Conference2021 IEEE 48th Photovoltaic Specialists Conference (PVSC)
Period20/06/2125/06/21

Bibliographical note

See NREL/CP-5900-81296 for paper as published in proceedings

NREL Publication Number

  • NREL/CP-5900-80242

Keywords

  • anneal
  • GaInP
  • III-V
  • multijunction

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