Ayarcı Kuruoglu N., Yetkin T., Bozkurt K., Özdemir O., Kulakci M.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY, cilt.41, sa.10, ss.1-24, 2026 (Scopus)
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Yayın Türü:
Makale / Tam Makale
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Cilt numarası:
41
Sayı:
10
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Basım Tarihi:
2026
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Doi Numarası:
10.1088/1361-6641/aeaf78
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Dergi Adı:
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
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Derginin Tarandığı İndeksler:
Applied Science & Technology Source, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC
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Sayfa Sayıları:
ss.1-24
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Yıldız Teknik Üniversitesi Adresli:
Evet
Özet
Abstract
A direct coupling methodology between Geant4 and SCAPS-1D is introduced for the accurate simulation of betavoltaic devices, and validated against experimental photovoltaic measurements on GaAs/AlGaAs heterostructures. Unlike conventional approaches that rely on empirical fitting functions for the carrier generation profile, the present work computes the depth-dependent energy deposition of a
63
Ni beta source directly using Geant4 with the Penelope low-energy physics constructor, converts the result to a volumetric electron–hole pair generation rate via the Klein relation, and imports it into SCAPS-1D as a user-defined profile. Six-layer and five-layer GaAs/AlGaAs n–p and p–n configurations are characterized under both AM1.5 G illumination and
63
Ni irradiation. Simulated photovoltaic parameters show good agreement with experiment for both junction polarities. Under betavoltaic operation, the n–p structures maintain a consistent relative efficiency advantage of approximately 9% over the p–n structures when bulk SRH defects are present, whereas for defect-free material the polarity difference lies within the parameter-set uncertainty. Removal of the heavily doped front GaAs cap layer improves betavoltaic efficiency by 54%–62% by eliminating parasitic absorption in the surface-peaked beta deposition region. Bulk SRH defects reduce efficiency by approximately 47–53%. Shunt resistance (
R
sh
) is identified as a critical design parameter: at nA cm
−2
current densities,
R
sh
≫ 20 MΩ·cm
2
is required to avoid severe fill factor degradation. Among the investigated structures, the defect-free n–p five-layer configuration achieved the highest simulated efficiency of 2.84% under 13.87 mCi cm
−2
63
Ni irradiation. A controlled sensitivity study using conventional bulk-GaAs effective densities of states (
N
c
= 4.21–4.70 × 10
17
cm
−3
) confirms that the cap-removal and defect conclusions are insensitive to this parameter choice, changing the maximum efficiency only marginally (from 2.84% to 2.82%), while lowering the open-circuit voltage of the defect-containing devices by 37–40 mV. The methodology provides a physically consistent framework for heterostructure betavoltaic device design and optimization.