Doping diamond exhibits excellent photoelectric properties, making it promising for applications in wide-bandgap semiconductors, high-temperature devices, and high-power electronics. However, research on n-type doping remains limited. This paper reviews the main n-type doping methods for diamond: ion implantation (I/I), chemical vapor deposition (CVD), high pressure–high temperature (HPHT), deuterated method (DM), surface charge transfer doping (SCTD), and laser irradiation (LI). It analyzes the parameters, advantages, and disadvantages of each technique while classifying common single-element and multi-element co-doping methods. Single-element dopants include Group IA (Li, Na, K), Group ⅡA (Be, Mg), Group VA (N, P, As, Sb), and Group ⅥA (O, S, Se, Te) elements. Multi-element co-doping often combines B-P, B-S, B-O, and B-N pairs. Additionally, we examine the atomic structures of these dopants, introduce commonly used simulation models, and compare the electronic characteristics of synthesized n-type doping diamonds. Finally, we summarize the challenges of n-type doping diamond in doping equipment, processes, and electronic devices, and propose possible improvements and future development directions.

Lanthanum oxide was introduced to molybdenum powder by liquid-liquid doping and liquid-solid doping respectively. Mo alloys were prepared by powder metallurgy technology. The size distribution and feature of dopant particles and the fractographs of Mo alloys were investigated by TEM and SEM respectively. The results indicated that liquid-liquid doping method is favorable for refining and dispersing particles uniformly in matrix. Fracture toughness of Mo alloys prepared by liquid-liquid doping showed better results than that of liquid-solid doping. Furthermore, the influences of the size distribution of on properties of Mo alloys was discussed by dislocation pile-up theory.