The influence of interfaces and the modulation doping technique on the magneto‐transport properties of HgTe based quantum wells

Abstract

Abstract The influence of interfaces in the structure of HgTe based quantum wells (QW's), their structure as well as the necessary technological processes on their transport properties have been investigated and either reduced or optimized. The mobility ( μ ) of the 2‐dimensional electron gas (2DEG) has been shown to increase when the separation of the 2DEG from the ionized donors is increased, and when the separation of the QW structure from both the insulator on top and the CdTe buffer interface is increased. Furthermore, replacing wet chemical etching in the Hall bar photolithography procedure with a dry plasma etch process resulted in a 2.5 fold increase in the μ . Values for μ up to 0.7 × 10 6 cm 2 /(Vs) at 4.2 K have been reproducibly achieved. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)