Department of Materials and Interfaces
Weizmann Institute of Science
Rehovot 76100, Israel
Semiconductor Quantum Dot Films
Our research centres around thin films of nanocrystalline semiconductor deposited by solution methods (chemical bath deposition and electrodeposition). We are interested in several aspects of these nanocrystalline films, as well as in various aspects of the deposition processes themselves.
Chemical bath deposited CdSe films on glass.
The numbers above the films give the crystal size in nm.
The electronic structure and therefore optical and electronic properties of the semiconductors vary as a function of crystal size (in this regime, the semiconductor nanocrystals are known as quantum dots). Besides learning to control quantum dot size, we also study interactions between neighbouring quantum dots (in aggregated films) which, for small enough quantum dots (< 4 nm) act to lower the degree of size quantization.
Because of the very high surface area of many of these films (typically several tens of percent of all atoms are surface atoms), they are particularly sensitive to adsorption of various species. We follow changes in properties (optical, electrical) with adsorption of various inorganic species.
Charge transport and solar cells
Charge transport in porous, nanocrystalline films is being investigated, with particular emphasis on the mechanisms of charge transport (usually space charge layer-free) and the effects of surface states on charge transport. We continue a long-term interest in various types of thin film solar cells.
Publications since 2001:
- Electroless Ni and NiTe2 Ohmic Contacts for CdTe/CdS PV cells. O. Rotlevi, K.D. Dobson, D.Rose and G. Hodes. Thin Solid Films, 387, 155 (2001).
- Identification of surface states on individual CdSe quantum dots by room temperature conductance spectroscopy, B. Alperson, I. Rubinstein and G. Hodes, Phys. Rev. B, 63, 081303(R) (2001).
- Preparation and surface structure of nanocrystalline cadmium sulfide (sulfoselenide) precipitated from dimethyl sulfoxide solutions. Rivka Elbaum, Shimon Vega and Gary Hodes, Chem. Mater., 13, 2272 (2001).
- Stabilizing CdTe/CdS solar cells with Cu-containing contacts to p-CdTe, K.D. Dobson, I. Visoly-Fisher, G. Hodes and D. Cahen, Adv. Mater., 13, 1495 (2001).
- Blue emission from cysteine ester passivated cadmium sulfide nanoclusters, S. Sapra, J. Nanda, D.D. Sarma, F. Abed El-Al and G. Hodes, Chem. Commun., 21, 2188 (2001).
- Formation and Characterization of Electroless-Deposited NiTe2 Back Contacts to CdTe/CdS Thin-Film Solar Cells, K. D. Dobson, O. Rotlevi, D.Rose and G. Hodes, J. Electrochem. Soc., 149, G147 (2002).
- Chemical solution deposition of silver halides, G. Hodes and G. Calzaferri, Adv. Funct. Mater., 12, 501 (2002).
- Molecules and Electronic Materials. D. Cahen and G. Hodes, Adv. Mater. 14, 789 (2002).
- Reversible adsorption-enhanced quantum confinement in semiconductor quantum dots, Shaibal Sarkar, Nirmala Chandrasekharan, Sasha Gorer and Gary Hodes, Appl. Phys. Lett. 81, 5045 (2002).
- The Silver Chloride Photoanode in Photoelectrochemical Water Splitting, D. Schürch, A. Currao, S. Sarkar, G. Hodes and G. Calzaferri, J. Phys. Chem. B, 106, 12764 (2002).
- Structural Effects in the Electrodeposition of CdSe Quantum Dots on Mechanically Strained Gold, I. Ruach-Nir, H. D. Wagner, I. Rubinstein and G. Hodes, Adv. Funct. Mater. 13, 159 (2003).
- Shape control in electrodeposited, epitaxial CdSe nanocrystals on (111) gold, I. Ruach Nir, Y. Zhang, R. Popovitz-Biro, I. Rubinstein and G. Hodes, J. Phys. Chem. B, 107, 2174 (2003).
- Thin Semiconductor Films for Radiative Cooling Application, Y. Mastai, K. D. Dobson and G. Hodes, Sol. En. Mater. Sol. Cells, 80, 283 (2003).
- Factors affecting the stability of CdTe/CdS solar cells, deduced from stress tests at elevated temperature. I. Visoly-Fisher, K.D. Dobson, Jayakrishnan Nair, Erez Bezalel, Gary Hodes and David Cahen, Adv. Funct. Mater., 13, 289 (2003).
- Nonaqueous electrodeposition of ZnO and CdO films, R. Jayakrishnan and G. Hodes, Thin Solid Films, 440, 19 (2003).
- Physical Chemical Principles of Photovoltaic Conversion with nanoparticulate, mesoporous dye-sensitized solar cells, J. Bisquiert, G. Hodes, A. Zaban, S. Rühle and D. Cahen, J. Phys. Chem. B, 108, 8106 (2004).
- Nanocrystalline CdSe Formation by Direct Reaction between Cd Ions and Selenosulphate Solution, Shira Yochelis and Gary Hodes, Chem. Mater., 16, 2740 (2004).
- Electrochemical preparation of H2S and H2Se, Stéphane Bastide, Paul Hügel, Claude Lévy-Clément and Gary Hodes, J. Electrochem. Soc., 152, D35 (2005).
- Internal field switching in CdSe quantum dot films on Si, Shaibal K. Sarkar, Hagai Cohen and Gary Hodes, J. Phys. Chem. B, 109, 182-187 (2005).
- Charge overlap interaction in quantum dot films: time dependence and suppression by cyanide adsorption, S. K. Sarkar and G. Hodes, J. Phys. Chem. B, 109, 7214-7219, (2005).
- CdSe-sensitized p-CuSCN/nanowire n-ZnO heterojunctions, C. Lévy-Clément, R. Tena-Zaera, M. A. Ryan, A. Katty, G. Hodes, Adv. Mater. 17, 1512, (2005).
- Chemical Solution Deposition of Semiconductor Films, G. Hodes, Marcel Dekker Inc., Oct. 2002.
- 2. Electrochemistry of Nanostructures, ed. G. Hodes, Wiley-VCH Publishers, (2001).
- Electrodeposition of semiconductor quantum dot films, G. Hodes and I. Rubinstein, In: Electrochemistry of Nanostructures, ed. G. Hodes, Wiley-VCH Publishers, p.25 (2001).
- Dye-sensitized solar cells: principles of operation, D. Cahen, M. Grützel, J.F. Guillemoles and G. Hodes, In: Electrochemistry of Nanostructures, ed. G. Hodes, Wiley-VCH Publishers, p.201 (2001).