Use of an ion gauge beam flux monitor for resistivity control in CuInSe 2 grown by molecular beam epitaxy

Abstract

We have constructed and utilized a miniature ion gauge to set the copper, indium and selenium fluxes for the growth of CuInSe 2 onto CdS to form solar photovoltaic heterojunctions. Resistivities from 0.01 Ω cm n type to 0.001 Ω cm p type can be reliably achieved to within a factor of 10 of the desired value. The copper-to-indium arrival rate ratio is critical in determining the layer resistivity of p-type material, with a high copper-to-indium ratio generally giving low resistivity. The selenium arrival rate is also important, however, in that low selenium rates always lead to n-type layers, independent of the copper-to-indium arrival rate ratio.