Doping of LPE layers of CdTe grown from te solutions

Good quality epitaxial layers of CdTe have been grown by LPE from Te-rich solutions at ˜ 500‡C onto (111) CdTe substrates. The layers have been characterised by a wide variety of techniques including capacitance-voltage profiling, photoluminescence at 4K and secondary-ion mass spectrometry (SIMS) . Undoped layers had good electrical properties (p ˜ 1 × 10¹⁶ cm⁻³, L_e ˜ 3 μm) and SIMS showed the layers to be of high purity. Those doped with In and Al however, had low n-type carrier concentrations and very short diffusion lengths, while the photoluminescence spectra showed a strong peak at ˜ 1.4 eV commonly seen in n-type bulk CdTe. The most heavily doped layers showed marked decreases in lattice parameter.