Oxidation of GaSb(100) and its control studied by scanning tunneling microscopy and spectroscopy

Abstract

<p> <span style="color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif;">Atomic-scale knowledge and control of&nbsp;</span><span class="named-content" style="margin: 0px; padding: 0px; border: 0px currentColor; border-image: none; color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif; vertical-align: baseline;">oxidation</span><span style="color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif;">&nbsp;of GaSb(100), which is a potential&nbsp;</span><span class="named-content" style="margin: 0px; padding: 0px; border: 0px currentColor; border-image: none; color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif; vertical-align: baseline;">interface</span><span style="color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif;">&nbsp;for energy-efficient transistors, are still incomplete, largely due to an amorphous structure of GaSb(100) oxides. We elucidate these issues with scanning-tunneling&nbsp;</span><span class="named-content" style="margin: 0px; padding: 0px; border: 0px currentColor; border-image: none; color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif; vertical-align: baseline;">microscopy</span><span style="color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif;">&nbsp;and spectroscopy. The unveiled oxidation-induced building blocks cause&nbsp;</span><span class="named-content" style="margin: 0px; padding: 0px; border: 0px currentColor; border-image: none; color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif; vertical-align: baseline;">defect</span><span style="color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif;">&nbsp;states above Fermi level around the conduction-band edge. By interconnecting the results to previous photoemission findings, we suggest that the&nbsp;</span><span class="named-content" style="margin: 0px; padding: 0px; border: 0px currentColor; border-image: none; color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif; vertical-align: baseline;">oxidation</span><span style="color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif;">&nbsp;starts with substituting second-layer Sb sites by oxygen. Adding small amount of indium on GaSb(100), resulting in a (4&thinsp;&times;&thinsp;2)-In reconstruction, before&nbsp;</span><span class="named-content" style="margin: 0px; padding: 0px; border: 0px currentColor; border-image: none; color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif; vertical-align: baseline;">oxidation</span><span style="color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif;">&nbsp;produces a previously unreported, crystalline&nbsp;</span><span class="named-content" style="margin: 0px; padding: 0px; border: 0px currentColor; border-image: none; color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif; vertical-align: baseline;">oxidized</span><span style="color: rgb(77, 77, 77); line-height: 19.2px; font-family: Arial, sans-serif;">&nbsp;layer of (1&thinsp;&times;&thinsp;3)-O free of gap states.</span></p>