Emission wavelength control of self-catalytic InP/GaInAs/InP core–multishell nanowire on InP substrate grown by metal organic vapor phase epitaxy

Abstract

InP nanowires and InP/GaInAs/InP core–multishell nanowires were successfully grown on an InP(111)B substrate by low-pressure metal organic vapor phase epitaxy (MOVPE) using an indium catalyst. The self-catalytic vapor–liquid–solid (VLS) mode was used to obtain high-quality nanowires in which a deposited indium droplet acts as the catalyst instead of a metal particle, as in the case of the conventional VLS mode. InP core nanowire structures dependent on growth temperature and preheating temperature were obtained. InP/GaInAs/InP core–multishell nanowire structures, densities, and optical properties were investigated at various flow rates of trimethylindium (TMI) during the growth of InP core nanowires and the growth time of the GaInAs shell layer was also studied. The growth volume and density of nanowires were mainly dependent on growth temperature and preheating temperature, respectively. The height of nanowires was dependent on the TMI flow rate in the InP core nanowire growth, and the thickness of GaInAs shell layer was controlled by adjusting the growth time of the GaInAs shell layer. The photoluminescence (PL) intensity increased with increasing nanowire height and the peak wavelength was controlled by adjusting the thickness of the GaInAs shell layer.

Electrical Properties of the Base‐Substrate Junction in Freestanding Core‐Shell Nanowires

“…Unfortunately, this method does not provide access to the base of the NWs, which is crucial for all bottom‐up grown devices. In particular, a broad pedestal region forms around the NW base, which has already been recognized in several studies, e.g., for indium‐containing NW compounds [ 26–30 ] or core‐shell NW heterostructures, [ 31–34 ] which may affect the overall electrical behavior. This is especially relevant for applications, in which the use of vertical, epitaxially grown NWs is desired, and applies, for example, to NW‐based photovoltaic cells, [ 35 ] tunnel diodes, [ 36 ] lasers, [ 12 ] or field effect transistors.…”