In situ monitoring of the c( 4 × 4) to the 2 × 4 surface phase transformation on GaAs(001) by grazing incidence X-ray diffraction

Arsenic-rich GaAs(0 0 1) surface structure

“…Utilizing UHV STM and/or other methods several other studies of the phase transition between the (2 Â 4) and the c(4 Â 4) reconstructions followed with different results. Some confirmed the structural model of the c(4 Â 4) reconstruction proposed by Biegelsen et al [65][66][67]. Other groups argue that the c(4 Â 4) surface does not result from a simple adsorption of As dimers on the (2 Â 4) units, but rather forms after the (2 Â 4) unit cells are melted [68][69][70].…”

Species intermixing and phase transitions on the reconstructed (001) surfaces of GaAs and InAs

“…Surface x-ray diffraction studies of the c͑4ϫ4͒-͑2ϫ4͒ transition also indicate strong disordering of the c͑4ϫ4͒ structure before the appearance of 2ϫ4 diffraction features. 10 In contrast to GaAs͑001͒ and InSb͑001͒, the STM images of InAs͑001͒ indicate much less clearly the atomic content of the upper layer ͓Fig. 2͑c͔͒.…”

“…For GaAs͑001͒, the majority of studies have concentrated on the transition between the Ga-stabilized 4ϫ2 and the As-stabilized 2ϫ4 reconstructions, 8,9 as well as between the 2ϫ4 and the c͑4ϫ4͒ reconstructions. [10][11][12] The InAs͑001͒ surface has been less comprehensively studied, although the InAs͑001͒ 2ϫ4 to 4ϫ2 transition has been compared in detail with that on GaAs͑001͒. 13 In this case, there is a distinct difference between the two materials, with a discontinuous transition with hysteresis occurring on InAs͑001͒, contrasting with the continuous transition that occurs on GaAs͑001͒.…”

Atomic placement of Al on the GaAs {001}c(4×4)reconstruction determined by angle-resolved secondary-ion mass spectrometry

“…[9][10][11][12] For clarity, a brief overview is given here to substantiate the clean, reconstructed GaAs ͕001͖ surface, upon which we have deposited Al, employed during our in situ experimental studies. Most research on GaAs ͕001͖ surfaces has focused on the (2ϫ4) reconstruction, [13][14][15][16][17][18][19][20] but a large body of information regarding the c(4ϫ4) reconstruction has been gathered as well. [13][14][15][16][17][21][22][23][24][25] Studies on the c(4ϫ4) reconstruction reveal that the surface is composed of dimers bound in the ͗011͘ direction with a bond length of 2.69Ϯ0.10 Å.…”

“…Most research on GaAs ͕001͖ surfaces has focused on the (2ϫ4) reconstruction, [13][14][15][16][17][18][19][20] but a large body of information regarding the c(4ϫ4) reconstruction has been gathered as well. [13][14][15][16][17][21][22][23][24][25] Studies on the c(4ϫ4) reconstruction reveal that the surface is composed of dimers bound in the ͗011͘ direction with a bond length of 2.69Ϯ0.10 Å. 22,23 It is generally accepted that the GaAs ͕001͖ c(4ϫ4) reconstruction is terminated with two layers of As with the top layer containing As dimers and the second layer containing a full layer of As, [13][14][15][16][21][22][23][24][25] although one study suggests that the second layer is composed of a mixture of Ga and As.…”