(Color online) (a) Dark field TEM cross-sectional image of the GaSb/InP(001) heterostructure taken by selecting the 004 reflection of GaSb. (b) High resolution TEM cross-sectional zoom of the interface showing the presence of interfacial misfit network. (c) Illustration of the coincidence epitaxial relationship between both lattices.
(Color online) Reciprocal space map around the (1 1 5) Bragg reflection of the InP substrate and the GaSb epilayer.
(Color online) (a) AFM topographic image (1 μm × 1 μm) of the GaSb layer surface grown on InP(001) substrate. The surface is showing a clear steps-and-terraces morphology with a step height of one monolayer as shown on the Z profile (b).
(Color online) (a) RHEED patterns recorded along the  and [1 0] azimuths of the reconstructed GaSb(001) surface after As-decapping. The III–V surface is presenting a (1 × 3) periodicity, corresponding to a Sb-stabilized surface reconstruction, as illustrated in (b).
(Color online) XPS Ga 3d (a) and Sb 3d (b) core level spectra of a 1-nm-thick Al2O3/GaSb/InP(001) heterostructure. The interface is free of interfacial suboxides.
(Color online) TEM picture of an Al2O3/GaSb/InP(001) heterostructure showing a very sharp oxide/III–V interface.
(a) IPE/PC yield as a function of photon energy in p-type GaSb(001)/Al2O3 MOS capacitors with Al (circles) or Au (squares) electrodes measured under positive (open symbols) and negative (closed symbols) voltage of 1 V applied to the metal. Vertical arrows indicate the energies of direct optical transitions in GaSb crystal. (b) Determination of the PC thresholds using Y 1/2–hν plots from the spectra shown in panel (a). The insert illustrates determination of the energy threshold of electron IPE from the GaSb VB to the Al2O3 CB using the Y 1/3–hν plot. Vertical lines mark the inferred thresholds.
(Color online) Room temperature (300 K) C–V characteristics of Al2O3/GaSb(Si)/InP MOS capacitors. Difference between the ideal and measured high frequency curves are shown in the inset.
(Color online) (a) Conductance mapping revealing the Fermi level trace from GaSb midgap to the valence band edge. (b) D it distribution as a function of the energy above EV for Al2O3/p-GaSb MOS capacitor. D it’s are extracted by conductance method with varying C–V measurement temperatures near valence band and Terman method around midgap.
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