Controlling electronic properties of cdte by adsorption of dicarboxylic acid derivatives: Relating molecular parameters to band bending and electron affinity changes

Advanced Materials

Volumn 9, Issue 9, 1997, Pages 746-749

  Cohen, Rami ^a   Bastide, Stéphane ^a   Cahen, David ^a   Libman, Jacqueline ^a   Shanzer, Abraham ^a   Rosenwaks, Yossi ^b  

^a WEIZMANN INSTITUTE OF SCIENCE   (Israel)

^b TEL AVIV UNIVERSITY   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

ADSORPTION; BINDING ENERGY; CARBOXYLIC ACIDS; CHEMICAL BONDS; CHEMISORPTION; DERIVATIVES; ELECTRONIC PROPERTIES; ENERGY GAP; FERMI LEVEL; MOLECULAR STRUCTURE; PHOTOLUMINESCENCE; SURFACE STRUCTURE;

BAND BENDING; ELECTRON AFFINITY; MOLECULAR ORBITALS;

SEMICONDUCTING CADMIUM COMPOUNDS;

EID: 0031552585     PISSN: 09359648     EISSN: None     Source Type: Journal    
DOI: 10.1002/adma.19970090915     Document Type: Article

References (40)

1. EA is the energy difference of electrons at vacuum (just outside the range of the image forces) and at the bottom of the conduction band at the surface. BB is the electric potential difference between the surface and bulk of the semiconductor.
2. W. Mönch, Semiconductor Surfaces and Interfaces, 2nd ed., Springer, Berlin 1995.
3. H. Lüth, Surfaces and Interfaces of Solids, 2nd ed., Springer, Berlin 1993.
4. M. Stutzmann, C. P. Herrero, Phys. Scr. 1989, 725, 276.
5. E. Yablonovitch, C. J. Sandroff, R. Bhat, T. Gmitter. Appl. Phys. Lett. 1987, 51, 439.
6. Y. Nemirovsky, D. Rosenfeld, J. Vac. Sci. Technol. A 1990, 8, 1159.
7. A. J. Nelson, S. P. Frigo, R. A. Rosenberg, J. Appl. Phys. 1994, 73, 1632.
8. B. A. Parkinson, A. Heller, B. Miller, J. Electrochem. Soc. 1979, 126, 954.
9. D. Cahen, R. Noufi, Appl. Phys. Lett. 1989, 54, 558.
10. K. Vaccaro, H. M. Dauplaise, A. Davis, S. M. Spaziani, J. P. Lorenzo, Appl. Phys. Lett. 1995, 67, 527.
11. C. J. Murphy, G. C. Lisensky, L. K. Leung, G. R. Kowach, A. B. Ellis, J. Am. Chem. Soc. 1990, 112, 8344.
12. G. C. Lisensky, R. L. Penn, C. J. Murphy, A. B. Ellis, Science 1990, 248, 840.
13. K. D. Kepler, G. C. Lisensky, M. Patel, L. A. Sigworth, A. B. Ellis, J. Phys. Chem. 1995, 99, 16011.
14. S. R. Lunt, G. N. Ryba, P. G. Santangelo, N. S. Lewis. J. Appl. Phys. 1991, 70, 7449.
15. J. W. Thackeray, M. J. Natan, P. Ng. M. S. Wrighton, J. Am. Chem. Soc. 1986, 108, 3570.
16. T. Uchihara, M. Matsumura, J. Ono, H. Tsubomura, J. Phys. Chem. 1990, 94, 415.
17. D. R. Neu, J. A. Olson, A. B. Ellis, J. Phys. Chem. 1993, 97, 5713.
18. G. J. Meyer, G. C. Lisensky, A. B. Ellis, J. Am. Chem. Soc. 1988, 110, 4914.
19. G. J. Meyer, L. K. Leung, J. C. Yu, G. C. Lisensky, A. B. Ellis, J. Am. Chem. Soc. 1989, 111, 5146.
20. A. Hagfeldt, M. Grätzel, Chem.Rev. 1995, 95, 49.
21. M. Bruening, E. Moons, D. Yaron-Marcovich, D. Cahen, J. Libman, A. Shanzer, J. Am. Chem. Soc. 1994, 116, 2972.
22. M. Bruening, E. Moons, D. Cahen, A. Shanzer, J. Phys. Chem. 1995, 99, 8368.
23. S. Bastide, R. Butruille, D. Cahen, A. Dutta, J. Libman, A. Shanzer, L. Sun, A. Vilan, J. Phys. Chem., 1997 101, 2678
24. M. Bruening, R. Cohen, J. F. Guillemoles, T. Moav, J. Libman, A. Shanzer, D. Cahen, J. Am. Chem. Soc., in press.
25. The measurements were made with a commercial instrument (Delta Phi Besocke, Jülich, Germany) in a Faraday box under atmospheric pressure. The measurement results were taken after the signal had stabilized. Surface photovoltage measurements were carried out using a Kelvin probe arrangement and grating monochromator (0.6 < hv < 2.5eV). The system is described in detail in L. Burstein, J. Bregman, Y. Shapira, J. Appl. Phys. 1991, 69, 2312.
26. Sample preparation is detailed elsewhere [21].
27. FTIR spectra were measured in transmission mode (Bruker FTIR 1FS66) with etched sample as background.
28. D. Lin-Vien, N. B. Colthup, W. G. Fateley, J. F. Grasselli, in The Handbook of Infrared and Raman Characteristic Frequencies of Organic Molecules, Academic, Boston 1991.
29. K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, Wiley, New York 1986.
30. G. B. Deacon, R. J. Phillips, Coord. Chem. Rev. 1980, 33, 227.
31. FTIR of the dicarboxylates did not enable us to determine the preferred mode of coordination because of unfavorable signal/noise, although unidentate coordination seemed to dominate.
32. 2/molecule, similar to malonic acid (V. Vogel, D. Möbius, J. Colloid Interface Sci. 1988, 126, 408).
33. We assumed that the extinction coefficients of Na-carboxylate and surface-bound Cd-carboxylate stretches are comparable.
34. Adsorption of DMDC increased the EA by 110 mV. This can be accounted for by the hydrogen bonding and even proton transfer between the molecules, as indicated by FTIR.
35. S. D. Evans, E. Urankar, A. Ulman, N. Ferris, J. Am. Chem. Soc. 1991, 113, 4121.
36. HOMO) from its ionization potential, IP (J. E. Huheey, E. A. Keiter, R. L. Keiter, Inorganic Chemistry: Principles of Structure and Reactivity, 4th ed., Harper Collins, New York 1993, p. 166) The LUMO energy levels of the dicarboxylic acids were thus derived from i) the π-π* transition of the measured UV-vis spectra of the molecules in acetonitrile, and ii) the tabulated IP values for the benzoyl parts of the molecules' phenyl groups in the gas phase [38]. In the case of the PMDC and PCDC molecules, we extrapolated the IP of the palmitoyl group from data for shorter alkyl chains, hexane to undecane. Although the absolute energies may well be shifted as a result of the approximations used in arriving at these values, their trends are unlikely to change. The fact that we mix solution with gas phase values is unlikely to have a large effect. For example, the solvent effect on the π-π* transition in benzene amounts to 4 meV (H. Sponer, Chem. Rev. 1947, 41, 281).
37. HOMO) from its ionization potential, IP (J. E. Huheey, E. A. Keiter, R. L. Keiter, Inorganic Chemistry: Principles of Structure and Reactivity, 4th ed., Harper Collins, New York 1993, p. 166) The LUMO energy levels of the dicarboxylic acids were thus derived from i) the π-π* transition of the measured UV-vis spectra of the molecules in acetonitrile, and ii) the tabulated IP values for the benzoyl parts of the molecules' phenyl groups in the gas phase [38]. In the case of the PMDC and PCDC molecules, we extrapolated the IP of the palmitoyl group from data for shorter alkyl chains, hexane to undecane. Although the absolute energies may well be shifted as a result of the approximations used in arriving at these values, their trends are unlikely to change. The fact that we mix solution with gas phase values is unlikely to have a large effect. For example, the solvent effect on the π-π* transition in benzene amounts to 4 meV (H. Sponer, Chem. Rev. 1947, 41, 281).
38. All of our CPD measurements, i.e., those yielding the energetics both before and after adsorption, were done in air. This means that our initial and final states are gas-solid, rather than liquid-solid ones. Therefore the model presents the molecule's energy in the gas phase and the surface energy in air. even though the molecule-surface interaction took place in solution.
39. CRC Handbook of Chemistry and Physics (Ed: D. R. Lide), CRC Press, Boca Raton, FL 1994.
40. Adsorption of BA overnight or for 10 min did not change the BB; CBA adsorption overnight induced a BB change (120 mV), in contrast to what is observed after adsorption for 10 min (< 50 mV). We ascribe this difference to the adsorption kinetics of BAs on CdTe and to the different crystal source [21].