TY - JOUR
T1 - Impact of the growth temperature on the performance of 1.70-eV Al0.22Ga0.78As solar cells grown by MBE
AU - Onno, Arthur
AU - Tang, Mingchu
AU - Oberbeck, Lars
AU - Wu, Jiang
AU - Liu, Huiyun
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/10/1
Y1 - 2017/10/1
N2 - Growth of high material quality Aluminum Gallium Arsenide (AlxGa1-xAs) is known to be challenging, in particular with an Al content x above 20%. As a result, the use of AlxGa1-xAs in devices requiring high minority carrier lifetimes, such as solar cells, has been limited. Nonetheless, it has long been established that the substrate temperature is a key parameter in improving AlxGa1-xAs material quality. In order to optimize the growth temperature of 1.70-eV Al0.22Ga0.78As solar cells, five samples have been grown by Solid-Source Molecular Beam Epitaxy (SSMBE) at 580 °C, 600 °C, 620 °C, 640 °C, and 660 °C, respectively. A strong improvement in performance is observed with increasing the growth temperature from 580 °C to 620 °C. An open-circuit voltage above 1.21 V has in particular been demonstrated on the sample grown at 620 °C, translating into a bandgap-voltage offset Woc below 0.5 V. Above 620 °C, performances – in particular the short-circuit current density – moderately decrease. This trend is confirmed by photoluminescence, current density versus voltage characterization under illumination, and external quantum efficiency measurements.
AB - Growth of high material quality Aluminum Gallium Arsenide (AlxGa1-xAs) is known to be challenging, in particular with an Al content x above 20%. As a result, the use of AlxGa1-xAs in devices requiring high minority carrier lifetimes, such as solar cells, has been limited. Nonetheless, it has long been established that the substrate temperature is a key parameter in improving AlxGa1-xAs material quality. In order to optimize the growth temperature of 1.70-eV Al0.22Ga0.78As solar cells, five samples have been grown by Solid-Source Molecular Beam Epitaxy (SSMBE) at 580 °C, 600 °C, 620 °C, 640 °C, and 660 °C, respectively. A strong improvement in performance is observed with increasing the growth temperature from 580 °C to 620 °C. An open-circuit voltage above 1.21 V has in particular been demonstrated on the sample grown at 620 °C, translating into a bandgap-voltage offset Woc below 0.5 V. Above 620 °C, performances – in particular the short-circuit current density – moderately decrease. This trend is confirmed by photoluminescence, current density versus voltage characterization under illumination, and external quantum efficiency measurements.
KW - A3. Growth temperature
KW - A3. Molecular Beam Epitaxy
KW - B2. Aluminum Gallium Arsenide
KW - B3. Solar cells
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U2 - 10.1016/j.jcrysgro.2017.07.011
DO - 10.1016/j.jcrysgro.2017.07.011
M3 - Article
AN - SCOPUS:85025119514
VL - 475
SP - 322
EP - 327
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
SN - 0022-0248
ER -