Photoemission Studies of the Ag/InP(110) Interface: Interfacial Reactions and Schottky Barrier Formation

1983 ◽  
Vol 25 ◽  
Author(s):  
W. G. Petro ◽  
T. Kendelewicz ◽  
I. A. Babalola ◽  
I. Lindau ◽  
W. E. Spicer

ABSTRACTRoom-temperature interfacial reactions at the Ag/InP (110) interface have been studied using soft x-ray photoemission spectroscopy of the In 4d and P 2p core levels. For low Ag coverages (less than 1 monolayer (ML)) no measurable change in core level shapes is observed, and the shift in core level position is due solely to band bending. At high Ag coverages (up to 72 ML) we observe dissociated In metal, P atoms near the surface, and Ag clustering. Fermi level movement is deduced from these spectra using a deconvolution technique, and pinning positions of 0.40 ± 0.05 eV below the conduction-band minimum for n-type and 0.5 ± 0.l eV above the valence-band maximum for p-type are found. These positions are in close agreement with calculations of native defect levels.

2018 ◽  
Vol 232 (5-6) ◽  
pp. 893-905 ◽  
Author(s):  
Elena Echeverría ◽  
George Peterson ◽  
Bin Dong ◽  
Simeon Gilbert ◽  
Adeola Oyelade ◽  
...  

Abstract We have used X-ray photoemission spectroscopy to study the interaction of gold (Au) with novel boron carbide-based semiconductors grown by plasma-enhanced chemical vapor deposition (PECVD). Both n- and p-type films have been investigated and the PECVD boron carbides are compared to those containing aromatic compounds. In the case of the p-type semiconducting PECVD hydrogenated boron carbide samples, the binding energy of the B(1s) core level shows a shift to higher binding energies as the Au is deposited, an indication of band bending and possibly Schottky barrier formation. In the case of the n-type boron carbide semiconductors the interaction at the interface is more typical of an ohmic contact. Addition of the aromatic compounds increases the change in binding energies on both n-type and p-type PECVD boron carbide semiconductors, and the gold appears to diffuse into the PECVD boron carbides alloyed with aromatic moieties.


1982 ◽  
Vol 18 ◽  
Author(s):  
R. Purtell ◽  
P. S. Ho ◽  
G. W. Rubloff ◽  
G. Holinger

The binding energy of the bulk Si 2p levels observed with soft X-ray photoemission can be used to monitor the band bending in the silicon space charge region when a metal is deposited onto the silicon surface. Changes in the 2p binding energy with metal coverage can then be used to determine the change in the Schottky barrier height as the metal-silicon contact is formed. By tuning the photon energy and therefore the photoemitted electron escape depth, chemical shifts (atomic environment effects) at the interface can be separated from the bulk band bending effects. When combined with annealing to produce in-depth atomic intermixing, the result may reveal information on the distribution of metal atoms at the interface and its effect on the barrier height.Measurements of the Schottky barrier height change as a function of palladium deposition were made on (2 × 1) p-type and (7 × 7) n-type Si(111) surfaces by monitoring Si 2p core level shifts in a bulk sensitive mode. The barrier height change reached 1/e of its final value at a palladium coverage of 2.9 Å. Several experiments have made it possible to relate the measured Si 2p core level monitor of band bending to absolute Schottky barrier heights in a fully consistent fashion. Therefore, these results provide a means to measure the barrier height in the initial stages of Schottky barrier formation (i.e. at low metal coverage) and to compare these observations with the chemical behavior of the interface at low coverage and with electrical measurements on bulk contacts. Since the Pd/Si Schottky barrier height is established at the bulk value within a coverage of 3–5 Å (even before the overlayer is metallic), the role of interface chemical bonds in determining the barrier height is paramount.This work was supported in part by the U.S. Office of Naval Research.


1992 ◽  
Vol 260 ◽  
Author(s):  
L. J. Brillson ◽  
I. M. Vitomirov ◽  
A. Raisanen ◽  
S. Chang ◽  
R. E. Viturro ◽  
...  

ABSTRACTThe influence of metallization and processing on Schottky barrier formation provides the basis for one of several fruitful approaches for controlling junction electronic properties. Interface cathodo-and photoluminescence measurements reveal that electrically-active deep levels form on GaAs(100) surfaces and metal interfaces which depend on thermally-driven surface stoichiometry and reconstruction, chemical interaction, as well as surface misorientation and bulk crystal quality. These interface states are discrete and occur at multiple gap energies which can account for observed band bending. Characteristic trends in such deep level emission with interface processing provide guides for optimizing interface electronic behavior. Correspondingly, photoemission and internal photoemission spectroscopy measurements indicate self-consistent changes in barrier heights which may be heterogeneous and attributable to interface chemical reactions observed on a monolayer scale. These results highlight the multiple roles of atomic-scale structure in forming macroscopic electronic properties of compound semiconductor-metal junctions.


2002 ◽  
Vol 734 ◽  
Author(s):  
X. D. Feng ◽  
D. Grozea ◽  
Z. H. Lu

ABSTRACTWe studied the poly [2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)/LiF/Al interface by angle-dependent X-ray photoemission spectroscopy (XPS). The changes in the C1s, O 1s, Al 2p core level spectra, and the evolution of O to C and Li to F atomic ratios at different photoelectron take-off angles were carefully analyzed. A reduced oxygen concentration with a LiF layer at the interface suggests that LiF can help reduce the oxidation of Al. The interface was found rich in Li+ ions, some of which might be attached to MEH-PPV to form “N type” doping. The electron injection layer consists of Li+doped MEH-PPV, LiF, Al oxides, and metallic Al.


2013 ◽  
Author(s):  
W.F. Zhang ◽  
C.H. Lee ◽  
C.M. Lu ◽  
T. Nishimura ◽  
K. Nagashio ◽  
...  

1998 ◽  
Vol 57 (19) ◽  
pp. 11846-11849 ◽  
Author(s):  
O. Akaki ◽  
A. Chainani ◽  
T. Takahashi ◽  
Y. Kashimura ◽  
R. Kato

1989 ◽  
Vol 148 ◽  
Author(s):  
L. J. Brillson ◽  
R. E. Viturro ◽  
S. Chang ◽  
J. L. Shaw ◽  
C. Mailhiot ◽  
...  

ABSTRACTRecent studies of interface states and band bending at metal / III-V compound semiconductor interfaces reveal that these junctions are much more controllable and predictable than commonly believed. Soft x-ray photoemission spectroscopy studies demonstrate a wide range of band bending for metals on many III-V compounds, including GaAs. Cathodoluminescence spectroscopy measurements show that discrete states form at the microscopic junction which can have a dominant effect on the band bending properties. Internal photoemission measurements confirm the bulk barrier heights inferred by photoemission methods. After separating out surface chemical and bulk crystal quality effects, one finds simple, predictive barrier height variations which follow classical Schottky behavior.


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