List of All National Projects
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“Development of the applications of a-Si:H, poly-Si and c-Si in photovoltaic and other microelectronic devices”
project INIC, CFMUL, line of action nº 6
Duration: 1979 to 1991
Responsible: L. Guimarães and R. Martins

Objectives
To establish the conditions to perform R&D activity in Portugal related to amorphous silicon and to define the conditions to start also activity in the filed of microelectronics

Summary of the results achieved
As a result of this activity it was established the conditions to have today excellent groups in Portugal working in the field of thin film silicon, the establishment of the first deposition systems of a-SI:H and the starting in Portugal with great success activity in the filed of production and characterization of amorphous silicon films and devices. Apart from that, it was also established the first activity in Portugal concerning microelectronic processes using c-Si.

Main papers published
M. VIEIRA, R. MARTINS, E. FORTUNATO, M. SANTOS, A. MAÇARICO, N. CARVALHO, L. GUIMARÃES. “Role of Carbon Incorporation on Structural and Transport Properties of a/?c-Si:C:H Films”. Portugal Physica, Vol. 20, (1989/1991), pp. 21-29.

S. SOALHEIRA, R. MARTINS, C. CARVALHO, I. BAÍA, L. GUIMARÃES. “Optoelectronic Properties Presented by Doped and Undoped Amorphous Silicon Films”. Portugal Physica, Vol. 20 (1991), pp. 31-37.

R. MARTINS, G. WILLEKE, E. FORTUNATO, I. FERREIRA, M. VIEIRA, M. SANTOS, A. MAÇARICO, L. GUIMARÃES. “Transport in µc-Six:Cy:Oz:H Films Prepared by a TCDDC System”. J. of Non-Cryst. Solids, Nº 114, (1989), pp. 486-488.

M. LAVADO, R. MARTINS, I. FERREIRA, G. LAVAREDA, E. FORTUNATO, M. VIEIRA, L. GUIMARÃES. “Electron Paramagnetic Resonance of Defects in Doped Microcrystalline Silicon”. Vacuum Tech. Applic. & Ion Phys., Vol. 39, Nº 7/8, (1989). pp. 791-794.

R. MARTINS, A.M. ANDRADE, M.S. SANEMATSU, E. FORTUNATO, L. GUIMARÃES. “Thin Film Transistors produced by spatial plasma separation method”. Int. Topical Conf. on hydrogenated amorphous silicon devices and technology, ed. J. Kanicki, pp. 178-181, (1988).

A.M. ANDRADE, M.S. SANEMATSU, F.J. FONSECA, C.A.M. ANDRADE, I. PEREYRA, R.F.P. MARTINS, E. FORTUNATO. “Amorphous Silicon Thin Film Field Effect Transistors”. 5th Latin-American Symp. on surf. phys. thin films and small particles SLAFS V, pp. 269-273 (1988).

R. MARTINS, N. CARVALHO, E. FORTUNATO, A. MAÇARICO, M. SANTOS, I. BAÍA, M. VIEIRA, L. GUIMARÃES. “Effects of U.V. Light on the Transport Properties of a-Si:H Films During Their Growth”. J. of Non-Cryst. Solids, Vols. 97 & 98, (1987), pp. 1399-1402.

R. MARTINS, A.G. DIAS, L. GUIMARÃES. “The Interpretation of the Electric and Optical Properties of a-Si:H Films Produced by r.f. Glow Discharge through Dark Conductivity, Photoconductivity and Pulse Controlled Capacitance/ Voltage Measurements”. J. of Non-Cryst. Solids, Vol. 57, (1983), pp. 9-22.

R. MARTINS, A.G. DIAS, L. GUIMARÃES. “The Effect of Static Electric and Magnetic Fields on the Optoelectronic Properties of Amorphous Hydrogenated Silicon Films Produced by r.f. Glow Discharge”. Portugal Physica, Vol. 14, (1983) pp. 81-94.
R. MARTINS. “Growth Rate of Amorphous Hydrogenated Silicon Alloys Produced Under Crossed Static Electric and Magnetic Fields”. Thin Solid Films, Vol. 90, (1982), pp. 26-34.

A.G. DIAS, L. GUIMARÃES, R. MARTINS. “The Effect of Static Electric and Magnetic Fields on the Optical Properties of Amorphous Hydrogenated Silicon Films Produced by r.f. Glow Discharge”. Thin Solid Films, Vol. 89, (1982), pp. 307-313.

L. GUIMARÃES, R. MARTINS, A.G. DIAS. “Photoresponse Time and Density of Localized States in the Mobility Gap of a-Si:H Alloys Prepared by r.f. Glow Discharge”. Journal de Physique, Colloque C4, Supplement au Nº10, Tome 42, (1981), pp. 609-612.

D.I. JONES, W.E. SPEAR, P.G. LE COMBER, S. LI, R. MARTINS. “Electronic Transport and Photoconductivity in Phosphorous-Doped Amorphous Germanium”. Phil. Mag. B, Vol. 39, Nº 2, (1979), pp. 147-158.

“Amorphous silicon solar cells”
JNICT, Gulbenkian e DGE
Duration: (1985/89).
Partners: CFM and FCTUNL
Responsible: L. Guimarães

Objective
To establish the process conditions to launch the activity in the field of production large area a-Si:H solar cells (sizes above 5cmx5cm!)

Summary of the results achieved:
Can be taken from the set of main publications mentioned below:

L. GUIMARÃES, M. SANTOS, A. MAÇARICO, N. CARVALHO, R. MARTINS. “Enhancement of Voc by n- and p-type µc-Si:C:H wide band gap material produced in a TCDDC system”. Clean and safe energy forever, Proc. of the ISES, eds T. Horigome, K. Kimura, T. Takakura, T. Nishino, I. Fujii, Vol. 1, pp.187-191 (1989).

R. MARTINS, L. GUIMARÃES. “Electro-optical properties of a-Si:H/?c-Si:H and a-Si:C:H/c-Si:C:H undoped and doped films produced by a TCDDC system”. Int. PVSEC-3, B-IIp-5, p.794 (1987).

R. MARTINS L. GUIMARÃES, E. FORTUNATO, M. VIEIRA, N. CARVALHO, M. SANTOS, I. FERREIRA. “Performances presented by a-Si:C:H (doped and undoped) films produced by a TCDDC system for PV applications”. Proc. 8th EC-PVSEC, Vol. I, ed. I. Solomon, B. Equer and P. Helm, pp. 653-660 (1988).

C. CARVALHO, O. FIGUEIREDO, E. FORTUNATO, R. MARTINS, A. MAÇARICO AND L. GUIMARÃES. “Influence of thin film structure on the optoelectronic properties of ITO layers produced by reactive thermal evaporation”. Proc. 8th EC-PVSEC, Vol. I, ed. I. Solomon, B. Equer and P. Helm, pp. 801-805 (1988).

R. MARTINS, M. SANTOS, E. FORTUNATO, A. MAÇARICO, M. LAVADO, I. FERREIRA, L. GUIMARÃES, J. GORDON, Y. SHAPIRA. “Surface induced effects on the structure and composition of thin film a-Si p.i.n solar cells”. Proc. 8th EC-PVSEC, Vol. I, ed. I. Solomon, B. Equer and P. Helm, pp. 851-854 (1988).

R. MARTINS, L. GUIMARÃES. “A New weakly absorbing and highly conductive (µc-Si:C:H) material produced by a TCDDC system”. Euroforum New En. Int. Cong., ed. H. S. Stephens & Associates, Vol. 3, pp. 132-134 (1988).

R. MARTINS, M. VIEIRA, E. FORTUNATO, M. SANTOS, I. FERREIRA, M. LAVADO, L. GUIMARÃES. “Performances presented by µc-Si:C:H n- and p-type films produced by a TCDDC system”. Int. Topical Conf. on hydrogenated amorphous silicon devices and technology, ed. J. Kanicki, pp. 35-38, (1988).

I. PEREYRA, M.P. CARRENO, R.K. ONMORI, A.M. ANDRADE, R. MARTINS. “Influence of a d.c. electric field on hydrogen incorporation and doping efficiency of a-Si:H films”. Proc. 7th EC-PVSEC, eds A. Goetzberger, W. Palz and G. Willeke, pp. 528-532 (1986).

M.S. SANEMATSU, I. PEREYRA, A.M. ANDRADE, R. MARTINS. “Highly uniform large area a-Si:H films”. Solar Cells, Vol. 14, (1985), pp. 281-287.

I. PEREYRA, A.M. ANDRADE, M.S. SANEMATSU, R. MARTINS. “Electro-optical characterization of amorphous silicon films deposited in a two consecutive decomposition and deposition chamber system”. Proc. 6th EC-PVSEC, eds W. Palz and F.C. Treble, pp. 717-721 (1985).

“Development of a solar cell module”
M.I., nº CDI-U/015/84 (1985/88).
Duration: 1985/88
Responsible: L. Guimarães

Objectives
To produce a prototype module based on amorphous silicon solar cells with areas above 25 cm2 deposited on SS substrates. This goal was achieved and a 1m2 was produced.

Main papers published

J.L. GUIMARÃES, R. MARTINS, E. FORTUNATO, I. FERREIRA, M. SANTOS, N. CARVALHO. “Use of µc-Si:H Wide Band Gap n- and p- Type Materials for Producing Solar Cells by a TCDDC System”. MRS Symp. Amorphous Silicon Technology, Vol. 118, pp. 617-620 (1988

R. MARTINS, L. GUIMARÃES, N. CARVALHO, M. QUINTELA, I. PEREYRA, A.M. ANDRADE. “Performances of inverted p.i.n. and SiC(B).i.n. a-Si:H solar cells produced on S.S. substrates”. Int. PVSEC-2, eds Yu Pei-Nuo, pp. 445-447 (1986).

R. MARTINS, L. GUIMARÃES, N. CARVALHO, A.M. ANDRADE, I. PEREYRA, M.S. SANEMATSU. “The role of I.T.O. layer on the performances of amorphous silicon solar cells produced in a two consecutive decomposition and deposition chamber system”. Proc. 6th EC-PVSEC, eds W. Palz and F.C. Treble, pp. 722-726 (1985).

Objectives
The aim of this projecty was to study the role of metal passivation to improve the performances of solar cells. To do so, devices based on Schottky dices were studied. Apart from that, the influence of the substarte on the properties of the films grown was also investigated

Summary of the results achieved
The set of results achieved can be taken from the publications below:
“Substrate Effect on the Electrical Properties of a-Si:H Thin Films and its Modification by Diffusion-Blocking Interlayers”. J. Vac. Sci. Technol. A 7 (4), (1989), pp. 2628-2631.
J. GORDON, Y. SHAPIRA, E. FORTUNATO, R. MARTINS, L. GUIMARÃES. “Modification of Electrical Conductivity of a-Si:H Thin Films by Diffusion-Blocking Interlayers”. Proc. of Vacuum Journal Society, (1988) - S. Diego (U.S.A.).