## 1 Introduction  
Two-dimensional (2D) transition metal dichalcogenides (TMDCs), such as MoS\({}_{2}\), have attracted considerable attention owing to the unique optical and electronic properties related to its 2D ultrathin atomic layer structure [1]. MoS\({}_{2}\) is becoming prevalent in post-silicon digital electronics and in highly efficient optoelectronics due to its extremely low thickness and its tunable band gap (E\({}_{\text{g}}\) = 1-2 eV) [2; 3]. Sparsely-layered MoS\({}_{2}\) displays light absorbing and luminescence capabilities, enabling photodetector operation [1; 3]. Several efforts have been made to further develop 2D TMDC photodetectors with ultrafast response and high responsivity [4], owing to the longer lifetime of their photo-generated carriers and higher photosensitivity than traditional semiconductors [5; 6; 7]. However, 2D TMDC photodetectors fabricated with transferred van der Waals heterostructures or chemical vapor deposition-grown hybrids are typically characterized with low responsivity. This is due to the lack of a photo-gain mechanism or by resilient photoconductivity in the heterojunction structure [8]. In order to realize MoS\({}_{2}\)-based complementary electronic circuits and optoelectronic devices, it is necessary for there to be a development of up-scalable techniques to achieve controlled doping of MoS\({}_{2}\). Recently, field-effect transistors (FETs) fabricated with MoS\({}_{2}\) thin films have exhibited an excellent on/off current ratio (10\({}^{6}\)-10\({}^{8}\)) with a high carrier mobility of around 200 cm\({}^{2}\) V\({}^{-1}\) s\({}^{-1}\), making them suitable for next-generation transistors [9]. For low-power, high-performance complementary logic applications, both \(p\)- and \(n\)-type MoS\({}_{2}\) FETs (NFETs and PFETs) must be developed. NFETs with an electron accumulation channel can be obtained using unintentionally doped \(n\)-type MoS\({}_{2}\). However, the fabrication of MoS\({}_{2}\) FETs with complementary \(p\)-type characteristics is challenging due to the significant difficulty of injecting holes into its inversion channel [10]. One approach is to use unconventional contacts resulting in a low Schottky barrier height for hole injection in MoS\({}_{2}\) PFETs. For example, MoO\({}_{\rm x}\) (2 \(<\) x \(<\) 3) contacts have been shown to be effective for hole injection into pristine MoS\({}_{2}\)[11]. A proper interface between MoO\({}_{\rm x}\) and MoS\({}_{2}\) layers is necessary for efficient hole injection. Alternatively, several \(p\)-type doping approaches for MoS\({}_{2}\) have been established. Examples initiated doping by incorporating substitutional niobium, Nb, atoms during chemical vapor deposition (CVD) growth and chemical doping with AuCl\({}_{3}\)[12; 13; 14]. However, substitutional doping during CVD growth is lacking in area selectivity and the adoption of AuCl\({}_{3}\) would be hampered by the risk of Au contamination. Plasma treatments with different species (including CF\({}_{4}\), SF\({}_{6}\), O\({}_{2}\), and CHF\({}_{3}\)) have also been found to achieve the desired property modifications of MoS\({}_{2}\)[15; 16; 17]. In the case of multilayer MoS\({}_{2}\), which is exposed to energetic F-plasma treatment, \(p\)-type doping of the exposed area has been shown. However, plasma treatment may cause significant etching of the MoS\({}_{2}\), which can directly affect the feasibility of the development of MoS\({}_{2}\) FETs with a thin channel region. Therefore, mild plasma treatments are essential to achieve the proper modification of MoS\({}_{2}\). In this work, we demonstrated a \(p\)-type multilayer MoS\({}_{2}\) enabled by selective-area doping using CHF\({}_{3}\) plasma treatment. Compared with single layer MoS\({}_{2}\), multilayer MoS\({}_{2}\) can carry a higher drive current due to its lower bandgap and multiple conduction channels. Moreover, it has three times the density of states at its minimum conduction band [18].