Photoluminescence Detection of Surface Oxidation Processes on InGaN/GaN Nanowire Arrays

Abstract

InGaN/GaN nanowire arrays (NWA) exhibit efficient photoluminescence (PL) in the green spectral range, which extends to temperatures well beyond 200 °C. Previous work has shown that their PL is effectively quenched when oxidizing gas species such as O 2 , NO 2 , and O 3 abound in the ambient air. In the present work we extend our investigations to reducing gas species, in particular to alcohols and aliphatic hydrocarbons with C 1 to C 3 chain lengths. We find that these species give rise to an enhancing PL response which can only be observed when the NWAs are operated at elevated temperature and in reactive synthetic air backgrounds. Hardly any response can be observed when the NWAs are operated in inert N 2 backgrounds, neither at room temperature nor at elevated temperature. We attribute such enhancing PL response to the removal of quenching oxygen and the formation of enhancing water adsorbates as hydrocarbons interact with oxygen species coadsorbed on the heated InGaN surfaces.

Selective area growth of GaN nanowires and nanofins by molecular beam epitaxy on heteroepitaxial diamond (001) substrates

“…Group III-nitride nanorods/nanowires (NWs) and nanowalls/ nanons (NFs) are expected to be applied in photo-catalysis, [1][2][3] sensing devices, [4][5][6][7] optoelectronics, [8][9][10][11][12][13][14] and high-power electronics. [15][16][17][18][19][20] In particular, selectively grown GaN nanostructures (NSs) benet from outstanding structural quality, e.g., due to strain relaxation and dislocation ltering, [21][22][23][24] making them a promising candidate for next-generation three-dimensional GaN-based NW/NF eld-effect transistors (NWFETs/FinFETs).…”

Chemically Sensitive Photoluminescence of InGaN/GaN Nanowire Heterostructure Arrays

“…We have studied the photoluminescence (PL) response of InGaN/GaN heterostructure nanowire arrays (NWA) while being exposed to different kinds of oxidizing and reducing gases as well as to humidity (Figure 1a) [6][7][8][9][10]. As III-nitrides tend to form thin, native surface oxide layers when exposed to ambient air, their chemical interactions are similar to those on more traditionally studied kinds of metal oxides (MOX).…”

“…No responses to reducing gases are observed when these are applied in inert N2 backgrounds. Reducing gas species therefore are detected in an indirect manner by consuming quenching oxygen adsorbates and by forming enhancing H2O ones as these interact with oxygen species co-adsorbed in reactive backgrounds of ambient or synthetic air [8,10]. A characteristic observed across all kinds of analytes is that the concentration dependence of the PL response, , , consistently follows Langmuir isotherms which are easy to interpret regarding adsorbate-specific adsorption energies :…”

Feather-Shaped InGaN Nanorods for Selective ppb-Level Detection of NO2 Gas at Room Temperature

“…Metal oxides have been widely utilized for NO 2 gas sensors; however, these metal oxides only work effectively at high temperatures. − Among the III-nitride semiconductor family, indium gallium nitride (InGaN) has become the cornerstone for optoelectronic materials due to its appealing electrical properties. The strong electron accumulation on the surface walls of InGaN is a key feature that promotes high surface conductivity . The accumulation of charge carriers in InGaN nanorods (NRs) is a definite advantage for oxide gas detection, compared to the use of GaN .…”

“…The strong electron accumulation on the surface walls of InGaN is a key feature that promotes high surface conductivity. 16 The accumulation of charge carriers in InGaN nanorods (NRs) is a definite advantage for oxide gas detection, compared to the use of GaN. 17 The Environmental Protection Agency (EPA) classifies nitrogen dioxide (NO 2 ) as one of the six major pollutant gases.…”