Molecular Beam Epitaxy of Cu-Doped BaSi2 Films on Si(111) Substrate and Evaluation & Qualification of Depth Profiles of Cu Atoms for the Formation of Efficient Solar Cells
The doping of Cu in the BaSi2 films grown by molecular beam epitaxy (MBE) with various Cu concentrations for the suitability of the solar cells was studied in this paper. The main objective of the present work is to investigate and compare the carrier concentration of Cu-doped BaSi2 films grown with different Cu Knudsen cell temperatures and qualify as a potential candidate for more efficient solar cells. The reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) measurements and secondary ion mass spectroscopy (SIMS), were used to determine the structure, depth profile and composition of the grown samples. The electrical properties like resistivity as well as carrier concentration were measured by using a four point probe method and Van der Pauw technique, respectively. During the MBE growth, different temperatures for Cu Knudsen cell ranging from 800 to 1200 °C were chosen and the optimum growth condition for both heavily doped n-type as well as p-type in the MBE was investigated. In our previous work, the Al, Sb doped BaSi2 were used as a potential candidate for the formation of pn-junction for solar cells, but the result was not encouraging one due to diffusion and segregation problems in the surface and BaSi2/Si interface regions. In the present work n-type BaSi2 layers with their dopant atoms uniformly distributed in the grown layers for the formation of high-quality of BaSi2 pn-junction with single crystal nature were successfully developed. The realizations to develop cost effective and more efficient solar cells are inevitable for both terrestrial as well as space applications.
Arshad Munir and Zaffar M. Khan
M. A. Khan et al., "Molecular Beam Epitaxy of Cu-Doped BaSi2 Films on Si(111) Substrate and Evaluation & Qualification of Depth Profiles of Cu Atoms for the Formation of Efficient Solar Cells", Advanced Materials Research, Vol. 326, pp. 139-143, 2011