Bias-Enhanced Optical pH Response of Group III–Nitride Nanowires

Abstract

We show that the photoluminescence intensity of GaN and InGaN nanowires in electrolytes sensitively responds to variations of the pH value and the applied bias. The realization of an electrochemical working point allows pH detection with a resolution better than 0.05 pH. The observed effects are attributed to bias-dependent nonradiative recombination processes competing with interband transitions. The results show that group III-nitride nanowires are excellently suited as nanophotonic pH sensor elements.

Electronic properties of air-exposed GaN(11-00) and (0001) surfaces after several device processing compatible cleaning steps

“…Indeed, a decrease of the GaN(1100) and (0001) surface potentials has been reported when decreasing the pH (i.e. increasing the H + concentration) of a solution in contact with these surfaces [47][48][49]. Along the same line, H atoms have been reported to passivate the surface states of an atomically clean GaN(1100) surface and to desorb at high temperature [50].…”

Correlation of electrochromic properties and oxidation states in nanocrystalline tungsten trioxide

“…Proton insertion, using 0.1 M H 2 SO 4 in H 2 O as an electrolyte, was carried out in a specially designed compact three-electrode cell (adapted from Wallys et al 22 ) consisting of a 3 M KCl Ag/AgCl reference electrode (E 0 = 0.21 V vs. SHE, Driref-450 microreference, WPI) and a platinum counter electrode. The geometrical area of the WO 3 working electrode was 0.07 mm 2 .…”

Elastic versus Plastic Strain Relaxation in Coalesced GaN Nanowires: An X-Ray Diffraction Study

“…The high nanowire density is advantageous for light emitting and energy harvesting devices as well as for sensing applications [13][14][15][16]. On the other hand, GaN nanowires coalesce during growth because of their proximity [17].…”