The reaction kinetics of illuminated
normaln‐normalInAs
etched in nitric acid have been studied. Nitrogen dioxide was observed to evolve when the test sample was immersed in the acid solution. The dissolution rates of
normalInAs
, determined by the inductively coupled plasma (ICP) technique, were high. The nitrogen dioxide evolution reaction is believed to be an autocatalytic process which is followed by nucleophilic attack of the
normalInAs
electrode in which the surface oxides are etched away. Nitrite is an essential catalyst for the reaction and is also involved in the formation of an indium complex. The possible role of the energy levels at the
normalsemiconductor/HNO3
interface are discussed in an attempt to explain the widely different reactivities of the four III–V semiconductors
normalInP
,
normalGaAs
,
normalGaP
, and
normalInAs
. The very much higher dissolution rate of
normalInAs
was discussed in terms of (i) the adequate overlap of the distribution function of the oxidizing agent (nitrate) with the
normalInAs
valence band, and (ii) the energetic instability of the electrons in the In‒As bonding orbitals. In contrast, the opposite is true in the case of the other III–V materials. In the latter materials, electron transfer can occur across the semiconductor/electrolyte interface only via low density surface states within the bandgap.