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3 International Letters of Chemistry, Physics and Astronomy

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Fabrication and Optoelectronic properties of Fluoride tin oxides/porous silicon/p-Silicon heterojunction

Hadi H. A.

International Letters of Chemistry, Physics and Astronomy

2014

Vol. 17, iss. 2

142--152

In this paper, formation of a nanostructure semi transparence fluoride tin oxides (FTO) by spray pyrolysis technique on porous silicon PS layer. Porous silicon PS layer was prepared by anodization of p-type silicon wafers to fabricate of the UV- Visible Fluoride-doped tin oxide /Porous silicon /p-Si heterojunction photodetector. Optical properties of FTO thin films were measured. The optical band gap of 3.77 eV for SnO2 : F for film was deduced. From (I-V) and (C-V) measurements, the barrier ØB height for FTO/PS diode was of 0.77, and the built in voltage Vbi, which was of 0.95 V. External quantum efficiency was 55 % at 500 nm which corresponding to peak responsivity of 1.15 A/W at 1 V bias. The PS band gap in the vicinity of PS/c-Si heterojunction was 1.38 eV.

An Effect Etching Time on Structure Properties of Nano-Crystalline p-type Silicon

Hadi H. A.

International Letters of Chemistry, Physics and Astronomy

2014

Vol. 17, iss. 3

327--333

This paper reports the influence of the etching time on structural characteristics of porous silicon manufactured by electrochemical etching (ECE) anodization p-type silicon wafers. Micro and nano-structural features of the samples are mainly investigated by XRD and AFM techniques. The morphological properties of PS layer such as nano-crystalline size, the structure aspect of PS layer and lattice constant have been investigated. Nanocrystals size (grain size) computing from XRD data (145 to 85) nm is resulting the increasing etching time.AFM investigations reveal increase in (RMS) roughness, Sz.(Ten Point height) and average diameter of the porous structure with increase in etching time.

Fabrication and characterization of porous silicon layer prepared by photo-electrochemical etching in CH3OH:HF solution

Hadi H.A., Ismail R.A., Habubi N.F.

International Letters of Chemistry, Physics and Astronomy

2013

Vol. 3

29-36

Porous silicon (PS) has been fabricated by Photo-electrochemical etching. Porous silicon was anodized on n-type Si in light using a current density of 20mA/cm2 for 10 min. The porous structure formation was confirmed using XRD and AFM studies. The root mean square (RMS) roughness of the Porous silicon layer is found to be around 47.5 nm and the ten point height was 317 nm. The average of pores diameter was 419.98nm, and the grain growth is columnar with a (211) preferred orientation. The grain size of the PS was estimated from the Scherer's formula and found to be 73 nm. All the properties of the porous silicon layer, such as porosity and the thickness depend on the anodization parameters. The porosity (P) was approximately 77 %. The thickness of the layer formed during an anodization in constant current was 3.54nm in gravimetric method, while its value was 1.77nm by using the theoretical relation.