1. REFERENCE [1] : Jin-Woo Han, Beomseok Kim, Nobuhiko P. Kobayashi, Jing Li, and M. Meyyappan, a simple method for the determination of doping type in nanomaterials based on electrical response to humidity, Appl. Phys. Lett. 101, 142110 (2012) Acknowledgments : This work is supported by West African Economic and Monetary Union (WAEMU) and the Senegalese Government Simple method for silicon n-type doping for solar cells application. Rémi NDIOUKANE 1, Mamadou BIAGUI 1,Waly BODIAN 1, Diouma KOBOR 1, Marie Amandine PINAULT 2 and François JOMARD 2 1 Laboratoire de Chimie et de Physique des Matériaux (LCPM), Université Assane Seck de Ziguinchor BP 523, Ziguinchor, Sénégal, dkobor@univ-zig.sn 2 Groupe d’Etude de la Matière Condensée (GEMaC), UMR8635 Université de Versailles St Quentin, France A p – type Si sample (a) after thin layer deposition, (b) thermal treatment and cleaning The Phosphorus 31 P concentration variation versus the substrate depth (c) standard (d) sample Thermal profile for annealing SIMS Analysis: In order to check if the doping is well done, a SIMS analysis was performed for this purpose Thin layer depositing apparatus: Spin Coater Midas 1200 D All analyzes were performed in primary Cs+/ negative secondary high mass resolution to remove 31P / 30Si1H interference (M / DELTA.M) = 4000. Conclusion : Introduction: The electrical behaviour of a semiconductor device depends strongly to the dopants distribution within the structure. To make solar cells from monocrystalline silicone, it is necessary to realize a pn junction by implanting phosphorus atoms mainly on a given thickness of the p-type. Different liquid, solid, or gaseous methods are used. These methods often require equipment not available for underdeveloped countries. In this work, we try to make mono-Si solar cells using an easier doping method. We combined spin-coating thin film deposition method and solid doping technique. This technique can be considered as the SOD method. The difference between these methods is the use of a phosphorus oxide gel as a dopant. Sample characteristics: resistivity : 5-10 Ω.cm orientation : 100 thickness (w) : 256-366 µm LCPM (a) Schematic illustration of the doping type determination method. The shift direction of current is monitored as a response of moisture. (b) The surface states of the material under atmospheric ambient. The surface is covered by oxygen ions. (c) The reaction between the moisture molecules with the rooted oxygen ions. The reaction releases electrons behind the material [1]. This test showed a p-type conduction before doping and a n-type after diffusion confirming that there is a change in the conductor type p into n. The surfaces usually contain negatively charged oxygen ions in an ambient environment, as shown in (b), which is more realistic. This state is considered typical as long as the materials are not contained under vacuum. As the moisture molecules arrive, H 2 O reacts with the O’s surface groups as shown in (c). In this case, the moisture molecules act as electron donors. The hydrogen of H 2 O and the surface oxygen become the hydroxide ion, while the oxygen of H 2 O and the surface oxygen induce desorption of O 2. This process releases electrons behind the channel. In other words, this reaction can also be interpreted as oxidation and reduction mechanism: H 2 O + 2O 2-  ½O 2 + 2OH - + 2e - As a result, the supply of electrons in n-type material reduces the resistance whereas the deficiency of holes in p-type material increases the resistance [1]. The presence of such electrons on the p-type surface induces the diffusion of holes toward the surface and recombination process which reduces the diffusion so the conduction. This resistance increase explains the opposite direction of the current. Sample method of conductor type determination DKRM4-2 DKRM4-1 Samples were carried out as shown in the figure. The signal intensity variation versus time for the (a) standard and (b) sample. Photos of craters of the SIMS analysis zones SIMS results showed that phosphorus was diffused into silicon with a maximum concentration of 10 19 to 10 20 at/cm 3. The depth of the phosphorus diffusion is approximately equal to 300 nm. MEB analysis shows good homogeneity of the layer deposited on the silicon substrate surface treated at 900°C. The objective of this work was to perform phosphorus doping in Si using sample and easy method for research purpose in developing countries. (a) (b) (c) (d) (a) [1] Senegal, Dakar, August, 03 - 23, 2014 (a) (b) (c) Photos of MEB analysis for 200 nm (a) 1µm (b) 100 nm (c) after diffusion (a) (b) African School of Physics and Applications 2014