Effects of passivation treatment on the surface stability in indium-doped Hg _0.8 Cd _0.2 Te epilayers grown on p-Cd _0.96 Zn _0.04 Te substrates

Passivation treatment on indium-doped Hg _0.8 Cd _0.2 Te epitaxial layers grown on p-Cd _0.96 Zn _0.04 Te substrates by molecular beam epitaxy has been performed in order to improve the surface stability of the Hg _0.8 Cd _0.2 Te layers. Room-temperature capacitance-voltage measurements clearly revealed metal-insulator-semiconductor (MIS) behavior for the Al/ZnS/passivated Hg _0.8 Cd _0.2 Te layer/Cd _0.96 Zn _0.04 Te diodes. The fast state density and the fixed charge density of the Al/ZnS/passivated Hg _0.8 Cd _0.2 Te/Cd _0.96 Zn _0.04 Te diode with a sulfur-treated Hg _0.8 Cd _0.2 Te layer were smaller than those with a chemically oxidized Hg _0.8 Cd _0.2 Te layer. The interface state density at the ZnS/sulfur-treated Hg _0.8 Cd _0.2 Te interface were low at 10 ¹¹ eV ^-1 cm ^-2 at the middle of the Hg _0.8 Cd _0.2 Te energy gap. These results indicate that the Hg _0.8 Cd _0.2 Te epilayer is significantly passivated by sulfur treatment and that the passivated Hg _0.8 Cd _0.2 Te layers can be used for Hg _1-x Cd _x Te-based MIS diodes and MIS field-effect transistors.