Physical properties enhancement of porous silicon treated with In2O3 as a antireflective coating

Electrical Characterization of MIS Schottky Barrier Diodes Based on Nanostructured Porous Silicon and Silver Nanoparticles with Applications in Solar Cells

“…The observed increase in τ 1 , τ 2 , and τ 3 for the Al/Si/TiO 2 /NiCr devices is related to the large thickness of the TiO 2 thin films and the large carrier recombination rates of Si [34], as previously indicated in the analysis of the Nyquist plots. The values obtained for τ 1 , τ 2 , and τ 3 for the Al/Si+nanoPS/TiO 2 /NiCr devices are attributed to conduction losses associated with the porous structure of the nanoPS layers, as well as with the formation of defects on their surface [35]. The combination of the nanoPS layers with metallic nanoparticles has a notable effect on the electrical conduction at the active layer/TiO 2 interfaces, which leads to a small value of τ 2 .…”

“…n shows the lowest value in this case. The increase in n observed for the Al/Si+nanoPS/TiO 2 /NiCr devices is attributed to the higher porosity of the surface of Si after the etching process, which causes an increase in the defects on the surface of the nanoPS layers [35]. The reduction of the value of the ideality factor for the Al/Si+nanoPS+AgNPs/TiO 2 /NiCr devices (n = 3.29) is considered a consequence of a change of the type of charge carrier recombination that is taking place in the active layer associated to the Ag nanoparticles embedded into nanoPS.…”

Hybrid porous silicon/silver nanostructures for the development of enhanced photovoltaic devices

“…The main reasons for photoresponse reduction for this device are discussed in detail in section 3.4.1. with the structure Al/Si/nanoPS/TiO2/Au. The Fermi level for nanoPS is located close to the middle of the energy gap [44,45] as a consequence of the formation of pores at defects and dopant sites of Si [16,44,46], thereby considerably reducing the doping concentration of Si and widening the energy gap of PS with respect to that Si (its energy band gap is 1.12 eV) [47]. We estimate the energy band gap value of nanoPS to be around 1.65 eV, corresponding to a porosity of 60.3% [47,48].…”

“…In the first variation (Al/Si/nanoPS/TiO2/Au devices), nanoPS is used as a wideband optical absorber [15]. However, this choice has two main drawbacks: (i) the surface of nanoPS is rapidly oxidized upon exposition to the atmosphere, leading to changes in its optical properties [16], and (b) two main recombination mechanisms can take place on the surface of nanoPS, namely radiative recombination through surface states (surface recombination) and through oxygen vacancies [17]. In this line, thin layers of In2O3 [16], SiO2 or SiO2/SiN [18], TiO2 [19] and Al2O3 or Al2O3/SiN have been used to passivate the surface of nanoPS [20].…”

“…However, this choice has two main drawbacks: (i) the surface of nanoPS is rapidly oxidized upon exposition to the atmosphere, leading to changes in its optical properties [16], and (b) two main recombination mechanisms can take place on the surface of nanoPS, namely radiative recombination through surface states (surface recombination) and through oxygen vacancies [17]. In this line, thin layers of In2O3 [16], SiO2 or SiO2/SiN [18], TiO2 [19] and Al2O3 or Al2O3/SiN have been used to passivate the surface of nanoPS [20]. Thin layers with high resistivity or even insulating nature in contact with the active layer of solar cells limit the amount of current that can flow into a small localized area, thus lowering the carrier mobility which improves cell efficiency as a result of an increase in the open-circuit voltage [21].…”