Transient and ac electrical transport under forward and reverse bias conditions in aluminum/porous silicon∕p-cSi structures

Abstract

Dielectric impedance measurements as well as transient current–voltage (I–V) characteristics under conditions of forward and reverse bias are reported in aluminum/porous silicon (PS)∕p-cSi structures at different temperatures. Under reverse bias conditions, the electrical conduction of the structures can be modeled by a simple equivalent circuit of two parallel RC networks in series combination, representing a bulk and a junction region. The bulk conduction is ohmic. From the detailed analysis of the PS/cSi junction, the carrier concentration NA and the depletion layer width W are evaluated at each temperature. The elapsed time t0 from the onset of the square pulse, at which the transition from the dominant bulk resistance to junction conduction takes place, is a function of temperature. As the temperature decreases, conduction due to bulk resistance dominates over junction conduction. On the other, hand forward conduction is dominated from the bulk. Two conduction mechanisms are present. As the time proceeds, Poole–Frenkel conduction follows an ohmic conduction. The time after the onset of the square voltage pulse, at which this turnover takes place, is a function of temperature.

Dielectric characterization of macroporous thick silicon films in the frequency range 1 Hz–1 MHz

“…For the sample with 72 nm thick oxide, the slope in a log-log plot is calculated to be ~1.0 in the whole voltage range used. This leads to the conclusion that the conductivity is ohmic [13][14][15]. As the thickness of the oxide layer decreases, another conduction mechanism prevails.…”

Impedance spectra under forward and reverse bias conditions in gold/porous silicon/p‐Si structures

“…Specifically, some authors proposed an electrical behaviour for PS structures controlled by the bulk conduction mechanism under forward bias conditions and controlled mainly by the junctions under reverse bias conditions [6,14]. On the other hand, some authors argue that the PS structures electrical behaviour, under forward and reverse bias conditions, is controlled principally by the junctions [15,16].…”

“…The material produced is known as porous silicon (PS) [3,4]. In order to investigate its electrical properties, two main porous silicon structures are formed by a p-Si wafer and two metal electrodes were used; aluminium [5,6] and gold [7,8]. The first structure produced it's a conductor type (metal/PS/metal) and the second structure formed it's a diode type (metal/PS/p-Si/metal) [2,6,8].…”

Effect of ethanol in an inorganic salt detector based on porous silicon

“…Much of the efforts have been focused on the improvement of the reliability in the electric operation of the devices. Some previous studies deal with the AC response of metal/PSi/Si systems in dry ambient for gas detection [15,16]. Some other applications need detection in wet environment, particularly when sensing pollutant anions in water.…”