Comparison of Triethylgallium and Trimethylgallium Precursors for GaInP Nanowire Growth

Abstract

Nanowire (NW) arrays containing a top segment of GaxIn1–xP are investigated, comparing NWs grown using two different Ga precursors, trimethylgallium (TMGa) and triethylgallium (TEGa). TMGa is the precursor commonly used for the particle‐assisted vapor–liquid–solid (VLS) growth of GaxIn1–xP NWs. However, it shows inefficient pyrolysis at typical NW growth conditions. The use of the alternative precursor TEGa is investigated by making a direct comparison between NWs grown using TEGa and TMGa at otherwise identical growth conditions. Growth rates, resulting NW materials composition, and time‐resolved photoluminescence (TRPL) lifetimes are investigated. With increasing Ga content of the NWs, the TRPL lifetimes decrease, indicating trap states that are associated with GaP. Somewhat longer TRPL lifetimes for the samples grown using TEGa indicate a lower concentration of deep trap states. For doped NWs, it is found that the strong effect of the p‐type dopant diethylzinc (DEZn) on the NW composition, observed for GaxIn1–xP NWs grown using TMGa, is absent when using TEGa.

Vertically Processed GaInP/InP Tandem-Junction Nanowire Solar Cells

“…For both the n-and isegments and the p-segment, the same trends are observed: an increased growth rate and lower Ga content x observed in the NWs after synthesis using increased χ TMIn , as could be expected intuitively and in accordance with previous experimental results. 35 We further characterized the samples by recording photoluminescence (PL) spectra of the as-grown NW arrays. Figure 2d shows the energy of the observed GaInP PL peak as a function of the composition determined by XRD.…”

“…While striving to keep the compositional variation of the GaInP subcell as small as possible, a certain variation along the NW axis is always present due to different surface diffusion properties of the In and Ga adatoms . Furthermore, the composition of the different segments is influenced by the dopants, in particular, Zn doping is known to affect the Ga x In 1– x P composition. , This effect is seen in Figure b, which shows the Ga x In 1– x P composition x as a function of the TMIn molar fraction χ TMIn separately for the p-segment and the n- and i-segments. For both the n- and i-segments and the p-segment, the same trends are observed: an increased growth rate and lower Ga content x observed in the NWs after synthesis using increased χ TMIn , as could be expected intuitively and in accordance with previous experimental results …”

“…For both the n- and i-segments and the p-segment, the same trends are observed: an increased growth rate and lower Ga content x observed in the NWs after synthesis using increased χ TMIn , as could be expected intuitively and in accordance with previous experimental results. 35 …”

Processing and characterization of large area InP nanowire photovoltaic devices

“…We use light-beam induced current (LBIC) mapping in combination with PL intensity mapping in order to gain an understanding of the device homogeneity, the presence of defects, and their nature. PL is commonly used to characterize as-grown NWs, both as standing NW arrays [24,50,51] and broken-off single NWs [52][53][54][55][56]. Recently, hyperspectral PL imaging was used on processed NW photovoltaic devices for extracting the quasi-Fermi level splitting [57].…”