Photovoltage and J-V features of porous silicon

Abstract

In this paper we present a systematic study into the influence of the electrical, structural and optical properties of the porous silicon (PS) layers on the photovoltage and J --V responses of devices prepared from this semiconductor material. Electronic devices were prepared forming a p- or n-type PS (pPS and nPS, respectively) layer on crystalline silicon c-Si (p- or n-type, pSi and nSi, respectively) substrate. Two different metals were deposited as contact electrodes. The devices' electrical responses analyzed were their current density versus voltage (J-V) and photovoltaic. It was found that the presence of the pPS layer significantly modifies the electrical responses mentioned above of the pSi material. It means the optoelectronics properties of the pSi are modified by the presence of the pPS layer; it can be understood in terms of the optical absorption spectra of PS. The nPS does not modify the optoelectronic properties of the nSi material. We propose an energy band diagram in order to explain the different behavior of these two different PS layers.