PbTe and Pb0.8Sn0.2Te epitaxial films on cleaved BaF2 substrates prepared by a modified hot-wall technique

Abstract

PbTe and Pb_0.8Sn_0.2Te epitaxial films have been grown on cleaved BaF₂ substrates by a modified hot‐wall technique. Relatively fast growth rates of 3–5 μm/h have been used to prepare high‐quality epitaxial films between 5 and 13 μm in thickness. Both p‐ and n‐type films have been grown by temperature control of a separate Te reservoir included in the apparatus. Carrier concentrations and mobilities in the orders of 2×10¹⁶–7×10¹⁷/cm³ and 1–3.3×10⁴ cm²/V sec, respectively, have been measured in the as‐grown films at 77 K. Pb_0.8Sn_0.2Te homojunction and PbTe‐Pb_0.8Sn_0.2Te heterojunction layers have been prepared. Diode elements engraved in the layers by mesa etching have shown R₀A products between 19 and 38 Ω cm² for heterojunction structures at 77 K.