Surface Modification of V–VI Semiconductors Using Exchange Reactions within ALD Half‐Cycles

• Published in: Advanced materials interfaces Vol. 5; no. 5
• Main Authors: Wiegand, Christoph W., Zierold, Robert, Faust, René, Pohl, Darius, Thomas, Andy, Rellinghaus, Bernd, Nielsch, Kornelius
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 09.03.2018
• Subjects: atomic layer deposition; Atomic layer epitaxy; Data analysis; Energy transmission; exchange reactions; Exchanging; II-VI semiconductors; Nanowires; Precursors; quartz crystal microbalance; Selenium; Substrates; Tellurium; topological insulator
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.201701155

The behaviors of tellurium and selenium atomic layer deposition vapor precursors, namely, Te(SiEt3)2 and Se(SiEt3)2, exposed to different V–VI semiconductor surfaces are reported. The interactions of the precursors with the substrates are monitored in situ with a quartz crystal microbalance (QCM) setup. Specifically, both the utilized metal–organic precursors interact with chalcogenide surfaces but differ in their reaction behaviors. Indeed, exchanged Te diffuses into the selenium‐containing substrate, whereas Se only exchanges with the top surface of the substrate. Transmission electron micrsocopy (TEM) and energy‐dispersive X‐ray spectroscopy (EDX/EDXS) analysis of the topological insulating nanowires reveals the single precursor interactions, which support the QCM data analysis, and provides insight into the morphological and crystalline structures of the altered substrates. Within an atomic layer deposition half‐cycle of single precursors, an exchange reaction on the interface between a V–VI semiconductor surface and the gaseous phase is described. The differences between tellurium‐ and selenium‐species are demonstrated and their interaction with the underlying substrate depicted. Cross sections of treated nanowires corroborate the findings and show the appearance of a diffusion gradient.