Effects of passivation treatment on the surface stability in indium-doped Hg 0.8Cd 0.2Te epilayers grown on p-Cd 0.96Zn 0.04Te substrates

Abstract

Passivation treatment on indium-doped Hg 0.8Cd 0.2Te epitaxial layers grown on p-Cd 0.96Zn 0.04Te substrates by molecular beam epitaxy has been performed in order to improve the surface stability of the Hg 0.8Cd 0.2Te layers. Room-temperature capacitance–voltage measurements clearly revealed metal-insulator–semiconductor (MIS) behavior for the Al/ZnS/passivated Hg 0.8Cd 0.2Te layer/Cd 0.96Zn 0.04Te diodes. The fast state density and the fixed charge density of the Al/ZnS/passivated Hg 0.8Cd 0.2Te/Cd 0.96Zn 0.04Te diode with a sulfur-treated Hg 0.8Cd 0.2Te layer were smaller than those with a chemically oxidized Hg 0.8Cd 0.2Te layer. The interface state density at the ZnS/sulfur-treated Hg 0.8Cd 0.2Te interface were low at 10 11 eV −1 cm −2 at the middle of the Hg 0.8Cd 0.2Te energy gap. These results indicate that the Hg 0.8Cd 0.2Te epilayer is significantly passivated by sulfur treatment and that the passivated Hg 0.8Cd 0.2Te layers can be used for Hg 1− x Cd x Te-based MIS diodes and MIS field-effect transistors.