The effect of chemical surface treatments on non-native (Bi2O3) GaAs metal-insulator-semiconductor solar cells

GaAs metal-insulator-semiconductor solar cells with a physically deposited Bi2O3 interfacial layer have been investigated. The deposition techniques used in the study were electron beam and boat thermal evaporation. The cells fabricated with interfacial layers of Bi2O3 showed a substantial improvement in open-circuit voltage over cells made without the physically deposited oxide layer. An etch has been used which yields an irregular ’’textured’’ surface. Cells employing this surface had a higher short-circuit current than those made with smooth, polished surfaces. The open-circuit voltages of these textured cells were lower than those with smooth surfaces. Calculations of the dependence of open-circuit voltage on pinhole density are in agreement with these results since a rough surface has a greater probability of pinholes.