Picosecond Photoluminescence Study of then-GaAs(100)/Methanol Interface in a Photoelectrochemical Cell

Abstract

Anodic photocorrosion and cathodic photowashing of n-GaAs(100) in a nonaqueous photoelectrochemical cell have been studied using photoluminescence decays and the voltage dependence of both photoluminescence intensity and photocurrent. Photocorrosion of the cell, which is attributed to trace water contamination, results in an increased surface recombination velocity and an overall loss in photoluminescence intensity, but does not affect the photocurrent. The stability of the photocurrent upon corrosion of the cell implies that the photoinduced surface states resulting from the corrosion are intrinsically different from those observed in all other systems studied previously in this laboratory. The techniques listed above were also used to monitor changes in the n-GaAs/methanol interface with incremental water additions to the cell to study the effects of water contamination.

The pH response of the InP/liquid ammonia interface at 223K: A pure nernstian behavior

“…In opposite, InP, presents an "unexpected" slope of 40 mV [3] if we consider the whole pH range. Two nernstian V fb behaviors were nevertheless observed for limited ranges of pH (0-4) and (8)(9)(10)(11)(12)(13)(14) while in the neutral pH range a non-nernstian variation was still detected. These behaviors revealed that a pure nernstian evolution depends essentially on the pH stability of the surface chemistry which supports the acid-base equilibrium [3].…”

“…According to the pH ranges, two different chemical compositions of InP surface were indeed determined by XPS chemical analyses. Either in acidic pH range (0-4) or basic pH range (8)(9)(10)(11)(12)(13)(14) a chemical composition close to a bare InP surface was determined, while a presence of a oxide mixture and hydroxide was analyzed only in neutral pH range [3]. How can we explain the nernstian potential variation observed onto a bare surface in aqueous media?…”

“…Non-aqueous solvent can be a suitable opportunity to modify the surface interaction that governs the interface building, allowing comparison that enriches our understanding of the interfacial structure. In past decades, many electrochemical processes have been studied in no aqueous solvents [8,9] but liquid ammonia (NH 3 liq.) appears to be among the most relevant to investigate original SC/electrolyte interfaces.…”

An ARXPS study of the passivating layer formed on III‐V surface by an innovative anodic treatment in liquid ammonia

“…water chemistry (e.g. Refs [7][8]). As a singular electrolyte, liquid ammonia (NH 3 liq) is distinguished from the other nonaqueous solvents since moisture does not interact at the interface.…”

Anodic Behavior of III-V Semiconductors in Liquid Ammonia (223 K)

“…Abshere et al [4,5] had clearly demonstrated the fact that the photocorrosion of GaAs is ruled by traces of water in anhydrous methanol.…”