On similar electrical, optical and structural properties of MOS structures prepared on a-Si:H/c-Si, porous silicon/c-Si, and c-Si Emil Pinčík *a , Hikaru Kobayashi b , Róbert Brunner a , Masao Takahashi b , Jaroslav Rusnák a , and Matej Jergel a a Institute of Physics of SAS, Dúbravska cesta 9, 845 11 Bratislava, Slovak Republic b ISIR, Osaka University and CREST, Japan Science and Technological Agency 8-1, Mihogaoka, Ibaraki, Osaka 567-0047, Japan email: emil.pincik@savba.sk Abstract. The paper presents results of research of similar electrical, optical and structural properties of three types of MOS structures prepared on different Si-based semiconductors. Electrical interface properties are investigated by institutionally produced equipment with Charge Version of Deep Level Transient Spectroscopy and time domain C-V. X-ray diffraction at grazing incidence angles is applied to control their structural properties. Optical properties of selected structures are investigated by photoluminescence measurements at liquid helium temperature (approx. 6K in cryostat). Dominant interest is focused on analysis of both electrical properties of MOS porous silicon based structures prepared on p-type crystalline Si and photoluminescence signals of the structures observed around 1.1 eV, respectively. Such parameters as Fermi level position, flat-band voltage, surface potential, position of deep level hole traps, and acceptor density are calculated for various conditions as defined by sample ambient, temperature, and light illumination. Following two main findings are analyzed: i) total suppression of large C-V hysteresis due to suitable illumination and ii) recovering of part of detected interface states in the dark. Introduction A large surface area and interfaces of porous silicon can make this semiconductor potentially useful for number of applications including formation photodiodes [1], batteries [2], fuel cells [3], [4], beta diodes [5]. Using porous silicon chemical detection through the developed sensors can be made [6], [7]. Well-defined pole array of porous silicon enables development of photonics [8], [9], [10]. There is possibility to perform catalysis through interaction of the porous silicon surface with chemically active nanostructures [11], [12]. The morphology, chemistry and electronic properties of the porous silicon surface can be tuned to fit the intended applications. The important property of porous silicon is broad range of achievable surface morphologies, which can be produced, with suitable modifications of technological condition of porous silicon preparation [13], [14]. Pores of the semiconductor can be prepared in specific direction only. Their average diameter is used to classify porous silicon as nanoporous (1-10 nm), mesoporous (10-100 nm) and microporous (greater than 100 nm). There are used also another classifications. In this contribution, we will present several similar electrical, optical and structural properties of metal-oxide-semiconductor structures prepared on a-Si:H/c-Si, porous silicon/c-Si, and c-Si. Materials Science Forum Vol. 609 (2009) pp 11-25 online at http://www.scientific.net © (2009) Trans Tech Publications, Switzerland Online available since 2009/Jan/06 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net. (ID: 147.213.112.15-06/01/09,15:05:06)