TY - JOUR
T1 - Investigation of dilute-nitride alloys of GaAsNx (0.01 < x < 0.04) grown by MBE on GaAs (001) substrates for photovoltaic solar cell devices
AU - Tang, Dinghao
AU - Vijaya, Gopi Krishna
AU - Mehrotra, Akhil
AU - Freundlich, Alex
AU - Smith, David
N1 - Funding Information:
The work was supported by the Engineering Research Center Program of the National Science Foundation (NSF) and the Office of Energy Efficiency and Renewable Energy of the Department of Energy (DOE) under NSF Cooperative Agreement No. EEC-1041895. The authors also acknowledge use of facilities in the John M. Cowley Center for High Resolution Electron Microscopy at Arizona State University.
Publisher Copyright:
© 2016 American Vacuum Society.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Dilute-nitride GaAsNx epilayers were grown on GaAs (001) substrates at temperatures of ∼450 °C using a radio-frequency plasma-assisted molecular/chemical beam exitaxy system. The concentration of nitrogen incorporated into the films was varied in the range between 0.01 and 0.04. High-resolution electron microscopy was used to determine the cross-sectional morphology of the epilayers, and Z-contrast imaging showed that the incorporated nitrogen was primarily interstitial. {110}-oriented microcracks, which resulted in strain relaxation, were observed in the sample with the highest N concentration ([N] ∼ 3.7%). Additionally, Z-contrast imaging indicated the formation of a thin, high-N quantum-well-like layer associated with initial ignition of the N-plasma. Significant N contamination of the GaAs barrier layers was observed in all samples, and could severely affect the carrier extraction and transport properties in future targeted devices. Dilute-nitride quantum-well-based photovoltaic solar cells were fabricated having a band-gap energy of 1.19 eV, which was attributed to the dilute-nitride layer.
AB - Dilute-nitride GaAsNx epilayers were grown on GaAs (001) substrates at temperatures of ∼450 °C using a radio-frequency plasma-assisted molecular/chemical beam exitaxy system. The concentration of nitrogen incorporated into the films was varied in the range between 0.01 and 0.04. High-resolution electron microscopy was used to determine the cross-sectional morphology of the epilayers, and Z-contrast imaging showed that the incorporated nitrogen was primarily interstitial. {110}-oriented microcracks, which resulted in strain relaxation, were observed in the sample with the highest N concentration ([N] ∼ 3.7%). Additionally, Z-contrast imaging indicated the formation of a thin, high-N quantum-well-like layer associated with initial ignition of the N-plasma. Significant N contamination of the GaAs barrier layers was observed in all samples, and could severely affect the carrier extraction and transport properties in future targeted devices. Dilute-nitride quantum-well-based photovoltaic solar cells were fabricated having a band-gap energy of 1.19 eV, which was attributed to the dilute-nitride layer.
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U2 - 10.1116/1.4940127
DO - 10.1116/1.4940127
M3 - Article
AN - SCOPUS:84954427208
SN - 2166-2746
VL - 34
JO - Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics
JF - Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics
IS - 1
M1 - 011210
ER -