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

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 approximate to p approximate to 1 x 10(19) cm(-3) and high carrier mobility similar to 10(4) cm(2) 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.