Liquid metal gallium-based printing of Cu-doped p-type Ga2O3 semiconductor and Ga2O3 homojunction diodes

As a promising third-generation semiconductor, gallium oxide (Ga2O3) is currently facing bottleneck for its p-type doping. The doping process of conventional semiconductors usually introduces trace impurities, which is a major technical problem in the electronics industry. In this article, we conceived that the process complexity could be significantly alleviated, and a high degree of control over the results could be attained using the selective enrichment of liquid metal interfaces and harvesting the doped metal oxide semiconductor layers. An appropriate mechanism is thus proposed to prepare the doped semiconducting based on multicomponent liquid metal alloys. Liquid metal alloys with the certain Cu weight ratios in bulk are utilized to harvest Cu-doped Ga2O3 films, which result in p-type conductivity. Then, field-effect transistors were integrated using the printed p and n-type Ga2O3 films and demonstrated to own excellent electrical properties and stability. Au electrodes fabricated on the printed Ga2O3 and Cu-doped Ga2O3 layers showed good Ohmic behavior. Furthermore, high-power diodes are realized using printed p and n-type Ga2O3 homojunction through combining van der Waals stacking with transfer printing. The fabricated Ga2O3 homojunction diode exhibited good efficiency at room temperature, involving a rectification ratio of 103 and forward current density at 10 V (J@10 V) of 1.3 mA. This opens the opportunity for the cost-effective creation of semiconductor films with controlled metal dopants. The process disclosed here suggests important strategies for further synthesis and manufacturing routes in electronics industries.