The use of alternative solvents for the low-temperature LPE growth of CdTe films

Abstract The use of alternative solvents, in particular Bi and In, has been investigated for the LPE growth of CdTe films at temperatures down to 250°C. In comparison with earlier work using Te as a solvent, this approach has several benefits: (i) improved surface topography; (ii) better solution removal; (iii) more abrupt interfaces; (iv) improved electrical properties. SIMS measurements showed that the layers grown from Bi solutions contained ∽0.1 ppma Bi, while those from In solutions contained ∽100 ppma In. Doping experiments with In, Sb and As were performed using Bi as the solvent. Estimated values for the segregation coefficients for growth at 500-400°C were k In ∽6×10 -4 , k Sb ∽10 -4 and k As ∽2×10 -3 . Layers grown from In solutions showed long minority carrier diffusion lengths ( L h ≳20 μm ) and very high luminescence efficiency, indicating extremely high quality CdTe.