Investigation of iodine as a donor in MBE grown Hg1-xCdxTe

N-type Hg1-xCdxTe layers with x values of 0.3 and 0.7 have been grown by molecular beam epitaxy using iodine in the form of CdI2 as a dopant. Carrier concentrations up to 1.1 x 10(18) cm(-3) have been achieved far x = 0.7 and up to 7.6 x 10(17) cm(-3) for x = 0.3. The best low temperature mobilities are 460 cm(2)/(Vs) and 1.2 x 10(5) cm(2)/(Vs) for x = 0.7 and x = 0.3, respectively. Using CdI2 as the dopant modulation doped HgTe quantum well structures have been grown. These structures display very pronounced Shubniliov-de Haas oscillations and quantum Hall plateaus. Electron densities in the 2D electron gas in the HgTe quantum well could be varied from 1.9 x 10(11) cm(-2) up to 1.4 x 10(12) cm(-2) by adjusting the thicknesses of the spacer and doped layer. Typical mobilities of the 2D electron gas are of the order of 5.0 x 10(4) cm(2)/(Vs) with the highest value being 7.8 x 10(4) cm(2)(Vs).