Valence-band offsets and Schottky barrier heights of layered semiconductors explained by interface-induced gap states

Many metal chalcogenides are layered semiconductors. They consist of chalcogen–metal–chalcogen layers that are themselves bound by van der Waals forces. Hence, heterostructures involving layered compounds are abrupt and strain-free. Experimental valence-band offsets of heterostructures between GaSe, InSe, SnS2, SnSe2, MoS2, MoTe2, WSe2, and CuInSe2 and between some of these compounds and ZnSe, CdS, and CdTe as well as barrier heights of Au contacts on GaSe, InSe, MoS2, MoTe2, WSe2, ZnSe, CdS, and CdTe are analyzed. The valence-band discontinuities of the heterostructures and the barrier heights of the Schottky contact compounds are consistently described by the continuum of interface-induced gap states as the primary mechanism that governs the band lineup at semiconductor interfaces.

[1]  Prediction and observation of II–VI/CuInSe2 heterojunction band offsets , 1994 .

[2]  R.L. Anderson.  Experiments on Ge-GaAs heterojunctions , 1962, IRE Transactions on Electron Devices.

[3]  W. Jaegermann,et al.  A photoemission study of barrier and transport properties of the interfaces of Au and Cu with WSe2(0001) surfaces , 1994 .

[4]  W. Jaegermann,et al.  Band lineup of lattice mismatched InSe/GaSe quantum well structures prepared by van der Waals epitaxy: Absence of interfacial dipoles , 1996 .

[5]  C. Mead,et al.  Surface barriers on layer semiconductors: GaS, GaSe, GaTe , 1969 .

[6]  Carver A. Mead,et al.  Fermi Level Position at Metal-Semiconductor Interfaces , 1964 .

[7]  W. Schottky,et al.  Zur Halbleitertheorie der Sperrschicht- und Spitzengleichrichter , 1939 .

[8]  D. R. Penn,et al.  Wave-Number-Dependent Dielectric Function of Semiconductors , 1962 .

[9]  K. Lynn,et al.  Comparison of polycrystalline Cu(In,Ga)Se2 device efficiency with junction depth and interfacial structure , 1995 .

[10]  N. Mott.  Note on the contact between a metal and an insulator or semi-conductor , 1938 .

[11]  J. Barrau,et al.  Au/InSe Schottky barrier height determination , 1990 .

[12]  H. Ohyama,et al.  Evaluation of the CdS/CdTe interface using free-electron laser internal photoemission technique , 1997 .

[13]  W. Mönch.  Empirical tight‐binding calculation of the branch‐point energy of the continuum of interface‐induced gap states , 1996 .

[14]  Lince,et al.  Schottky-barrier formation on a covalent semiconductor without Fermi-level pinning: The metal-MoS2(0001) interface. , 1987, Physical review. B, Condensed matter.

[15]  Niles,et al.  Band offsets and interfacial properties of cubic CdS grown by molecular-beam epitaxy on CdTe(110). , 1990, Physical review. B, Condensed matter.

[16]  W. Jaegermann,et al.  Experimental determination of quantum dipoles at semiconductor heterojunctions prepared by van der Waals epitaxy , 1997 .

[17]  Volker Heine,et al.  Theory of Surface States , 1965 .

[18]  R. Williams,et al.  Au/ZnSe contacts characterized by ballistic electron emission microscopy , 1996 .

[19]  K. Sunouchi,et al.  Summary Abstract: Fabrication of ultrathin heterostructures with van der Waals epitaxy , 1985 .

[20]  M. Contreras,et al.  Chalcopyrite Cu(In,Ga)Se2 and defect-chalcopyrite Cu(In,Ga)3Se5 materials in photovoltaic PN junctions , 1997 .

[21]  A. Baldereschi,et al.  Mean-Value Point in the Brillouin Zone , 1973 .

[22]  W. Mönch.  Chemical trends of barrier heights in metal-semiconductor contacts: on the theory of the slope parameter , 1996 .

[23]  C. Mead.  Surface barriers on ZnSe and ZnO , 1965 .

[24]  H. Abe,et al.  Heteroepitaxy of Layered Semiconductor GaSe on a GaAs(111)B Surface , 1991 .

[25]  K. Ueno,et al.  Heteroepitaxial growth by Van der Waals interaction in one-, two- and three-dimensional materials , 1991 .