Fig. 3: Structural analysis of Ga2Se3 on Al2O3 and GaP/Si.
From: MOCVD growth of covalent and 2D GaxSey: a phase validation and characterization
a 5 × 5 µm2 AFM image showing up to 1 µm Ga2Se3 clusters with rod-like features on GaP/Si. b 2 × 2 µm2 AFM image of smaller Ga2Se3 clusters on Al2O3 under identical growth conditions. c Raman spectra corresponding to the samples shown in (a) and (b) exhibit vibrational modes consistent with Ga2Se3 as reported in literature64,65,66,67. Substrate-related peaks above 350 cm−1 are not marked for clarity but are consistent with reported spectra68,69,70,71,72,73, and the corresponding Raman spectra of the substrates are provided in the Supplementary Information (Fig. S7). d HAADF image of a Ga2Se3 cluster. Carbon deposition and tungsten deposition used for FIB sample preparation appear as dark and bright contrast above the cluster, respectively. Rod-like features similar to those observed in (a) are present. Additionally, a thin film containing Ga2Se3 is visible beneath the cluster. e HAADF image adjacent to the cluster, revealing the thin Ga2Se3 layer on the GaP substrate with ordered vacancies along the {111} planes and characteristic ‘sawtooth’-like antiphase domains (APDs). EDX analysis verifies the stoichiometry, yielding a Ga:Se ratio of 2:3, as shown in Fig. S8. f HAADF image of the Ga2Se3/GaP interface, illustrating an epitaxial relation of the Ga2Se3 layer to the underlying GaP. g HAADF image of the ordered vacancies, revealing a van der Waals-like boundary along the {111} plane, analogous to 2D GaSe. Across the APD boundary, gallium and selenium atomic positions are reversed.
