US EPA

4594913 

Journal Article 

Phosphorous doped p-type MoS2 polycrystalline thin films via direct sulfurization of Mo film 

Momose, T; Nakamura, A; Daniel, M; Shimomura, M 

2018 

8 

2 

10.1063/1.5019223 

WOS:000426580900009 

We report on the successful synthesis of a p-type, substitutional doping at S-site, MoS2 thin film using Phosphorous (P) as the dopant. MoS2 thin films were directly sulfurized for molybdenum films by chemical vapor deposition technique. Undoped MoS2 film showed n-type behavior and P doped samples showed p-type behavior by Hall-effect measurements in a van der Pauw (vdP) configuration of 10 x 10 mm(2) area samples and showed ohmic behavior between the silver paste contacts. The donor and the acceptor concentration were detected to be similar to 2.6 x 10(15) cm(-3) and similar to 1.0 x 10(19) cm(-3), respectively. Hall-effect mobility was 61.7 cm(2)V(-1)s(-1) for undoped and varied in the range of 15.5 similar to 0.5 cm(2)V(-1)s(-1) with P supply rate. However, the performance of field-effect transistors (FETs) declined by double Schottky barrier contacts where the region between Ni electrodes on the source/drain contact and the MoS2 back-gate cannot be depleted and behaves as a 3D material when used in transistor geometry, resulting in poor on/off ratio. Nevertheless, the FETs exhibit hole transport and the field-effect mobility showed values as high as the Hall-effect mobility, 76 cm(2)V(-1)s(-1) in undoped MoS2 with p-type behavior and 43 cm(2)V(-1)s(-1) for MoS2:P. Our findings provide important insights into the doping constraints for transition metal dichalcogenides. (c) 2018 Author(s).