Atomic-scale nature of the (3×3)-ordered GaAs(001):N surface prepared by plasma-assisted molecular-beam epitaxy

Abstract

In situ scanning tunneling microscopy and time-resolved reflection high-energy electron diffraction measurements were performed to study the nitridation process of the As-terminated GaAs(001)-(2×4) surface by using electron cyclotron resonance plasma-assisted molecular-beam epitaxy. We report the real-space atomic structure of the coherently strained (3×3)-ordered GaN monolayer on GaAs(001) after a limited-exposure nitridation process and the atomically smooth morphology of this nitrided surface. The unique (3×3) phase is found consisting of nitrogen dimers and a regular array of missing nitrogen rows in both [1̄10] and [110] directions.

As4 overpressure effects on the phase purity of cubic GaN layers grown on GaAs substrates by RF-MBE

“…The (3 × 3) reconstruction is a strained GaN monolayer almost fully N-terminated [14,16]. Following this monolayer, the transition to an unreconstructed (1 × 1) pattern was observed.…”

“…At this stage, the RHEED pattern of GaAs turns into a (3 × 3) pattern during the first 3s, that corresponds to the first strained c-GaN monolayer. In this monolayer, c-GaN is grown by replacing As by N in the cubic lattice of GaAs, which is an anion exchange reaction [16]. This reaction is a result of the higher bond energy of Ga N (96.8kcal mol −1 ) compared to Ga As (47.7kcal mol −1 ) [14].…”

Atomically controlled doping of nitrogen on GaAs(001) surfaces

“…The binding energy of Ga-N is much larger than that of Ga-As. According to detailed scanning tunneling microscopy (STM) observation, Gwo et al [3] proposed a (3 Â 3)-reconstruction model with N dimers and N-vacancy rows as shown in Fig. 3.…”

GaN Growth by Remote Plasma MOCVD: Chemistry and Kinetics by Real Time Ellipsometry

“…There, the OES spectra are dominated by the N 2 1st positive system [7], which indicates a considerable amount of N-atoms and of electronically and vibrationally excited N 2 molecules impinging on the growth surface. Any contribute of ions is absent and the importance of this can be understood by considering that the ionized portion of the N 2 plasma beam has been suggested to have detrimental effect on the GaN film morphology and crystallinity [9]. Figure 3 shows the XRD measurements for GaN on both α-Al 2 O 3 (0001) and GaAs (001) substrates from which the crystallographic structure has been derived.…”