Semiconductor | An-Najah Staff

n-GaAs Band-Edge Repositioning by Modification with Metalloporphyrin/Polysiloxane Matrices

Wed, 2013-04-24 13:01 — Samar Al Shakhshir

Journal Title, Volume, Page:

Active and Passive Electronic Components Volume 26 (2003), Issue 1, Pages 11-21

Year of Publication:

2003

Link:

http://www.hindawi.com/journals/apec/2003/651253/cta/

Authors:

Samar Shakhshir

Department of Chemistry, An-Najah National University, Nablus, Palestine

Current Affiliation:

Department of Chemistry, An-Najah National University, Nablus, Palestine

[email protected]

Hikmat S. Hilal

Department of Chemistry, An-Najah National University, Nablus, Palestine

Moayad Masoud

Department of Chemistry, An-Najah National University, Nablus, Palestine

Najeh Jisraw

Department of Chemistry, An-Najah National University, Nablus, Palestine

Preferred Abstract (Original):

Tetra(-4-pyridyl)porphyrinatomanganese(III)sulfate, MnP, (in the forms of MnIII and MnII mixture), was embedded into a polysiloxane polymer matrix and attached to the surfaces of n-GaAs wafers. The n-GaAs=polymer=MnP system was annealed under nitrogen and used for photoelectrochemical study in water=LiClO4=Fe(CN)3 6 = Fe(CN)4 6 system. The results indicated a positive shift in the value of the flat-band potential of the semiconductor due to MnP. This was manifested by shifting the values of the dark-current onset potential and the photo-current open-circuit potential towards more positive values. These findings are potentially valuable in future applications of solar energy in hydrogen and oxygen production from water.

n-GaAs Band-Edge Repositioning by Modification with Metalloporphyrin/Polysiloxane Matrices

Wed, 2010-04-21 14:32 — Hikmat S. Hilal, D.Sc.

Journal Title, Volume, Page:

Active and Passive Electronic Components Volume 26 (2003), Issue 1, Pages 11-21

Year of Publication:

2003

Link:

http://www.hindawi.com/journals/apec/2003/651253/cta/

Authors:

Hikmat S. Hilal

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestinian Authority

Current Affiliation:

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine

[email protected]

Moayyad Masoud

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestinian Authority

Samar Shakhshir

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestinian Authority

Najeh Jisraw

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestinian Authority

Preferred Abstract (Original):

Tetra(-4-pyridyl)porphyrinatomanganese(III)sulfate, MnP, (in the forms of MnIII and MnII mixture), was embedded into a polysiloxane polymer matrix and attached to the surfaces of n-GaAs wafers. The n-GaAs=polymer=MnP system was annealed under nitrogen and used for photoelectrochemical study in water=LiClO4=Fe(CN)3 6 = Fe(CN)4 6 system. The results indicated a positive shift in the value of the flat-band potential of the semiconductor due to MnP. This was manifested by shifting the values of the dark-current onset potential and the photo-current open-circuit potential towards more positive values. These findings are potentially valuable in future applications of solar energy in hydrogen and oxygen production from water.

Controlling Charge-Transfer Processes at Semiconductor/Liquid Junctions

Wed, 2010-04-21 14:32 — Hikmat S. Hilal, D.Sc.

Journal Title, Volume, Page:

Electrochimica Acta Volume 51, Issue 28, 15 September 2006, Pages 6487-6497

Year of Publication:

2006

Link:

http://www.sciencedirect.com/science/article/pii/S0013468606005044

Authors:

Hikmat S. Hilal

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine

Current Affiliation:

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine

[email protected]

John A. Turner

National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401, USA

Preferred Abstract (Original):

The interfacial kinetics of charge transfer at n-GaAs/liquid junctions were controlled by anchoring positively charged species, such as tetra(-4-pyridyl)porphyrinatomanganese(III), with the semiconductor surface. Unlike earlier adsorption techniques, the charges have been chemically anchored to the semiconductor surface, in this work, via a ligand. The number of charges per site (attached molecule) ranged from +1 to +5. The positive charges shifted the band-edges towards more positive potential values. The degree of shift increased with surface charge density. In the dark, the flat band potential (measured by Mott–Schottky technique) and the onset potential were shifted by up to 300 mV depending on surface charge density. Relatively less of a shift was observed during illumination of the system. Other surface characteristics, such as conversion efficiency and photoluminescence intensity, have been enhanced. The basis for these shifts and their implications with respect to control of interfacial processes are discussed.