Organic-Inorganic Junctions formed on Porous Silicon: Isolation of a Surface Configuration primary to the Luminescence Mechanism.

1992 ◽  
Vol 283 ◽  
Author(s):  
T. R. Cottrell ◽  
J. B. Benziger ◽  
J. C. Yee ◽  
J. K. M. Chunt ◽  
A. B. Bocarslyt
Keyword(s):  
Porous Silicon ◽  
Conducting Polymers ◽  
Ohmic Contacts ◽  
Primary Component ◽  
Solution Ph ◽  
Porous Silicon Surface ◽  
Surface Configuration ◽  
Schottky Type ◽  
P Type

ABSTRACTOrganic-inorganic junctions were formed between porous silicon and various conjugated conducting polymers, poly(3-methylthiophene) and polypyrrole. Schottky type barriers were observed between the conducting polymers in their doped state and p and n-type porous silicon. In their undoped state the conducting polymers behave like p-type semiconductors. Consistent with this, ohmic contacts were observed between undoped conducting polymers and p-type porous silicon while rectifying behavior typical of a p-n junction was observed for conducting polymers deposited onto n-type porous silicon. During characterization of the porous silicon substrate, an investigation of the surface chemistry revealed a strong correspondence between solution pH and the luminescence intensity of porous silicon. Surface titration experiments were performed on p and n-type porous silicon and the results indicate that a monoprotic surface acid with a pKa between 3–4 is a primary component in the luminescence mechanism of porous silicon.

Brønsted and Lewis Base Quenching of Photoemission from Luminescent ‘Porous Silicon’: Surface Protons in the Luminescence Mechanism

1992 ◽  
Vol 283 ◽  
Author(s):  
J. K. M. Chun ◽  
A. B. Bocarsly ◽  
T. R. Cottrellt ◽  
J. B. Benzigert ◽  
J. C. Yee
Keyword(s):  
Porous Silicon ◽  
Silicon Surface ◽  
Blue Shift ◽  
Primary Component ◽  
Lewis Base ◽  
Temperature Sensitive ◽  
Quenching Mechanism ◽  
Porous Silicon Surface ◽  
Hydration State ◽  
P Type

ABSTRACTThe photoluminescence (PL) observed from porous silicon (PS) is found to be very sensitive to pH. Brønsted bases quench the PL and simultaneously produce a blue shift of the p-type PS emission. Similarly, PL of n-type PS is quenched, but the emission is red shifted. Exposure to acids enhances PL and reverses the quenching due to base exposure. A pKa of 3–4 was determined for PS formed on both n- and p-type substrates, and identifies an acidic surface proton as a primary component in the PL mechanism. Variations in the intensity and energy distribution of PL as a function of temperature suggest that: 1) small changes in the hydration state of the surface may affect the emission, and 2) at least two luminescent species exist on the surface of PS; one of which is pH and temperature sensitive. SO2, a Lewis base, also quenches the PL of p-type PS quickly and reversibly. Exposure to acid is unnecessary for restoration of the PL. In contrast to reactivity with Brønsted bases, the reversibility with SO2 argues for a different quenching mechanism. Preliminary experiments show that PL is significantly quenched, ∼2–5%, by concentrations of ∼30ppm SO2 in Ar.

Improved electrical characterization of Al–Ti ohmic contacts on p-type ion implanted 6H-SiC

2003 ◽  
Vol 18 (6) ◽  
pp. 554-559 ◽  
Author(s):  
F Moscatelli ◽  
A Scorzoni ◽  
A Poggi ◽  
G C Cardinali ◽  
R Nipoti
Keyword(s):  
Ohmic Contacts ◽  
Electrical Characterization ◽  
P Type ◽  
Ion Implanted

scholarly journals Macropore Formation and Pore Morphology Characterization of Heavily Doped p-Type Porous Silicon

2019 ◽  
Vol 166 (2) ◽  
pp. B9-B12 ◽  
Author(s):  
David Martín-Sánchez ◽  
Salvador Ponce-Alcántara ◽  
Paula Martínez-Pérez ◽  
Jaime García-Rupérez
Keyword(s):  
Porous Silicon ◽  
Pore Morphology ◽  
Heavily Doped ◽  
P Type ◽  
Morphology Characterization ◽  
Macropore Formation

Structural and Morphological Characterization of Al/Ti-Based Ohmic Contacts on p-Type 4H-SiC Annealed Under Various Conditions

2000 ◽  
Vol 338-342 ◽  
pp. 1017-1020 ◽  
Author(s):  
Konstantin Vassilevski ◽  
Konstantinos Zekentes ◽  
George Konstantinidis ◽  
N. Papanicolaou ◽  
Irina P. Nikitina ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Morphological Characterization ◽  
P Type

Anodic oxidation of p- and p+-type porous silicon: surface structural transformations and oxide formation

1996 ◽  
Vol 276 (1-2) ◽  
pp. 76-79 ◽  
Author(s):  
J.L Cantin ◽  
M Schoisswohl ◽  
A Grosman ◽  
S Lebib ◽  
C Ortega ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Anodic Oxidation ◽  
Silicon Surface ◽  
Structural Transformations ◽  
Oxide Formation ◽  
Porous Silicon Surface ◽  
P Type

Electrochemical and Chemical Deposition of II-VI Semiconductors in Porous Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
R. Herino ◽  
M. Gros-Jean ◽  
L. Montes ◽  
D. Lincot
Keyword(s):  
Porous Silicon ◽  
Chemical Deposition ◽  
Porous Films ◽  
Concentration Gradients ◽  
Strong Concentration ◽  
Acidic Solutions ◽  
Semiconductor Compounds ◽  
Metallic Cations ◽  
P Type

AbstractThe introduction of II-VI semiconductor compounds into porous silicon layers has been investigated in order to obtain transparent and conducting contacts with the inner surface of the material. CdTe and ZnSe have been electrodeposited cathodically on n type nanoporous electrodes from acidic solutions containing the metallic cations and dissolved oxides of selenium or tellurium. CdS incorporation into p-type porous silicon has been achieved by chemical bath deposition, from solutions containing cadmium complexes and thioacetamid as a sulfur donor. Characterization of the deposits has been performed by SEM observations, X-ray analysis and RBS. Results confirm the penetration of the compounds into the porous films, with small to strong concentration gradients in thickness depending on the deposition method. After deposition and sample drying, the luminescence of CdTe embedded layers has almost disappeared, whereas those containing ZnSe and CdS show a photoluminescence efficiency which is not severely degraded.

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