TY - JOUR
T1 - Selective p-Doping of 2D WSe2via UV/Ozone Treatments and Its Application in Field-Effect Transistors
AU - Yang, Sujeong
AU - Lee, Geonyeop
AU - Kim, Jihyun
N1 - Publisher Copyright:
© 2021 American Chemical Society. All rights reserved.
PY - 2021/1/13
Y1 - 2021/1/13
N2 - Development of two-dimensional (2D) semiconductor devices with good Ohmic contact is essential to utilize their full potential for nanoelectronics applications. Among the methods that have been introduced to reduce the Schottky barrier in 2D material-based electronic devices, charge transfer doping has attracted significant interest because of its efficiency, simplicity, and compatibility with the microelectronic fabrication process. In this study, 2D WSe2-based field-effect transistors (FETs) were subjected to selective UV/ozone treatment to improve the Ohmic contact by forming WOX with a high work function, which induced hole doping in the neighboring WSe2 via electron transfer. The atomic force microscopy, cross-sectional transmission electron microscopy, and micro-Raman spectroscopy analyses confirmed the self-limiting formation of WOX while maintaining the crystallinity of the underlying WSe2. The channel layer of the back-gated 2D WSe2 FETs was encapsulated using 2D hexagonal boron nitride to prevent the UV/ozone-induced oxidation. By contrast, the regions that were in contact with the underlying metal electrodes were open, which allowed area-selective p-doping in the 2D WSe2. Our study demonstrated that the Ohmic-like behaviors obtained after area-selective UV/ozone treatment improved the electrical properties of the 2D WSe2-based FETs such as the field-effect mobility (improvement of 3-4 orders of magnitude) and current on/off ratio (improvement of five orders of magnitude), while maintaining the p-type normally-off characteristics. These results provide useful insights into an effective and facile method to reduce contact resistance in 2D semiconductor materials, thereby enhancing the electrical performances of 2D material-based electronic devices.
AB - Development of two-dimensional (2D) semiconductor devices with good Ohmic contact is essential to utilize their full potential for nanoelectronics applications. Among the methods that have been introduced to reduce the Schottky barrier in 2D material-based electronic devices, charge transfer doping has attracted significant interest because of its efficiency, simplicity, and compatibility with the microelectronic fabrication process. In this study, 2D WSe2-based field-effect transistors (FETs) were subjected to selective UV/ozone treatment to improve the Ohmic contact by forming WOX with a high work function, which induced hole doping in the neighboring WSe2 via electron transfer. The atomic force microscopy, cross-sectional transmission electron microscopy, and micro-Raman spectroscopy analyses confirmed the self-limiting formation of WOX while maintaining the crystallinity of the underlying WSe2. The channel layer of the back-gated 2D WSe2 FETs was encapsulated using 2D hexagonal boron nitride to prevent the UV/ozone-induced oxidation. By contrast, the regions that were in contact with the underlying metal electrodes were open, which allowed area-selective p-doping in the 2D WSe2. Our study demonstrated that the Ohmic-like behaviors obtained after area-selective UV/ozone treatment improved the electrical properties of the 2D WSe2-based FETs such as the field-effect mobility (improvement of 3-4 orders of magnitude) and current on/off ratio (improvement of five orders of magnitude), while maintaining the p-type normally-off characteristics. These results provide useful insights into an effective and facile method to reduce contact resistance in 2D semiconductor materials, thereby enhancing the electrical performances of 2D material-based electronic devices.
KW - Ohmic contact
KW - UV/ozone treatment
KW - charge transfer doping
KW - contact resistance
KW - two-dimensional (2D) materials
UR - http://www.scopus.com/inward/record.url?scp=85100030437&partnerID=8YFLogxK
U2 - 10.1021/acsami.0c19712
DO - 10.1021/acsami.0c19712
M3 - Article
C2 - 33379863
AN - SCOPUS:85100030437
VL - 13
SP - 955
EP - 961
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 1
ER -