Electrical characterization of visible emitting electroluminescent Schottky diodes based on n-type porous silicon and on highly doped n-type porous polysilicon

A. Ferrari*^, N. Lacquaniti*, S. La Monica*, G. Maiello*, G. Masini*, S. Lazarouk+, V. Bondarenko+ and P. Jaguiro+

⁺ Bielorussian State University of Informatics and Electronics, P Brovki 6 220600 Minsk Byelorussia
^* Universita di Roma 'La Sapienza', Facolta di Ingegneria, Dipartimento di Ingegneria Elettronica, Via Eudossiana 18 00184 Rome Italy

Abstract

The electrical behaviour of electroluminescent Schottky diodes fabricated on the base of aluminum and n-type porous silicon is reported. Porous silicon was formed by electrochemical etching in HF aqueous solutions of n-type monocrystalline silicon and of degenerate n⁺-type polysilicon. The polysilicon layer was formed on monocrystalline silicon substrate by low pressure chemical vapour deposition (LPCVD). The electroluminescence (EL) starting voltage was in the range 4-20 Volt, depending on the doping level of Si substrate; polysilicon samples showed a higher starting voltage. Developed devices showed broad EL spectra, covering the whole visible range. Electrical measurements include current-voltage characteristics and capacitance-voltage characteristics. Time response and stability of the light emitting devices was also measured, showing excellent speed and reliability characteristics.