Melt growth of bulk Bi2Te3 crystals with a natural p–n junction

Abstract

Single crystals of Bi₂Te₃ were grown from Bi–Te melts using the modified Bridgman method. It was shown for the first time that solidification of 61 and 62 mol.% Te melts provides a built-in p–n junction on the cleaved plane of as grown crystals without any post growth treatment. The formation of a p–n junction along the growth crystal was explained by Te segregation. Both p- and n-parts of the ingot have shown high carrier concentrations n ≈ p ≈ 1 × 10¹⁹ cm⁻³ and high carrier mobility ~10⁴ cm² V s⁻¹ at 4 K. In the transition p–n region, Hall carrier concentration is decreased by two orders of magnitude as a result of intrinsic compensation of carriers.