TY - GEN
T1 - Growth temperature optimization of interfacial misfit technique for growth of GaSb subcells on GaAs substrates
AU - Mansoori, A.
AU - Addamane, S. J.
AU - Renteria, E. J.
AU - Shima, D. M.
AU - Mangu, V. S.
AU - Vadiee, Ehsan
AU - Honsberg, Christiana
AU - Balakrishnan, G.
N1 - Funding Information:
This material is based upon work primarily supported by the National Science Foundation (NSF) and the Department of Energy (DOE) under NSF CA No. EEC-1041895. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect those of NSF or DOE.
Publisher Copyright:
© 2018 IEEE.
PY - 2018/11/26
Y1 - 2018/11/26
N2 - Access to lattice matched narrow bandgap semiconductors is a challenge for improved efficiency of GaAs based multi-junction solar cells (MJSCs). GaSb has a bandgap of 0.72 eV and is ideally suited to be used as a Near-Infrared subcell for MJSCs. However, when used as a replacement for Germanium in GaAs based MJSCs, the large lattice mismatch between GaSb and GaAs results in significant threading dislocation density in the GaSb subcell. The threading dislocation density in the GaSb epilayer can be reduced to a certain extent by the realization of 90° interfacial misfit dislocation arrays (IMF) between the GaSb and GaAs layers. The substrate temperature during the growth of the GaSb epi-layer on GaAs has a strong impact on the threading dislocation density while making use of the IMF technique. In this study, several substrate temperatures (ranging from 350°C to 540°C) are explored to achieve reduced threading dislocation density which is measured using both plan-view Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) rocking curve analysis. A low growth temperature (of 420°C) shows the reduction of threading dislocation to the level of ∼1.3×10 8 cm -2 .
AB - Access to lattice matched narrow bandgap semiconductors is a challenge for improved efficiency of GaAs based multi-junction solar cells (MJSCs). GaSb has a bandgap of 0.72 eV and is ideally suited to be used as a Near-Infrared subcell for MJSCs. However, when used as a replacement for Germanium in GaAs based MJSCs, the large lattice mismatch between GaSb and GaAs results in significant threading dislocation density in the GaSb subcell. The threading dislocation density in the GaSb epilayer can be reduced to a certain extent by the realization of 90° interfacial misfit dislocation arrays (IMF) between the GaSb and GaAs layers. The substrate temperature during the growth of the GaSb epi-layer on GaAs has a strong impact on the threading dislocation density while making use of the IMF technique. In this study, several substrate temperatures (ranging from 350°C to 540°C) are explored to achieve reduced threading dislocation density which is measured using both plan-view Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) rocking curve analysis. A low growth temperature (of 420°C) shows the reduction of threading dislocation to the level of ∼1.3×10 8 cm -2 .
KW - GaSb
KW - IMF
KW - growth temperature optimization
KW - interfacial misfit array
KW - thermophotovoltaic
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U2 - 10.1109/PVSC.2018.8547684
DO - 10.1109/PVSC.2018.8547684
M3 - Conference contribution
AN - SCOPUS:85059877421
T3 - 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC
SP - 917
EP - 920
BT - 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 7th IEEE World Conference on Photovoltaic Energy Conversion, WCPEC 2018
Y2 - 10 June 2018 through 15 June 2018
ER -