Formation of a vertical SnSe/SnSe2 p-n heterojunction by NH3 plasma-induced phase transformation

Yi Li, Juanmei Duan, Yonder Berencén, René Hübner, Hsu Sheng Tsai, Chia Nung Kuo, Chin Shan Lue, Manfred Helm, Shengqiang Zhou, Slawomir Prucnal

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Layered van der Waals crystals exhibit unique properties making them attractive for applications in nanoelectronics, optoelectronics, and sensing. The integration of two-dimensional materials with complementary metal-oxide-semiconductor (CMOS) technology requires controllable n- and p-type doping. In this work, we demonstrate the fabrication of vertical p-n heterojunctions made of p-type tin monoselenide (SnSe) and n-type tin diselenide (SnSe2). The p-n heterojunction is created in a single flake by the NH3-plasma-assisted phase transformation from SnSe2 to SnSe. We show that the transformation rate and crystal quality strongly depend on plasma parameters like plasma power, temperature, partial pressure, NH3 flow, and duration of plasma treatment. With optimal plasma parameters, the full transformation of SnSe2 flakes into SnSe is achieved within a few seconds. The crystal quality and the topography of the fabricated SnSe-SnSe2 heterostructures are investigated using micro-Raman spectroscopy and cross-sectional transmission electron microscopy. The formation of a p-n junction is verified by current-voltage measurements.

Original languageEnglish
Pages (from-to)443-449
Number of pages7
JournalNanoscale Advances
Issue number2
Publication statusPublished - 2022 Nov 25

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • General Chemistry
  • General Materials Science
  • General Engineering


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