Integration of Monolayer n-MoS₂ with p-Type Boron Doped Diamond for Near Ideal 2D/3D p-n Heterojunction Rectifiers Operating at Room Temperature

Diamond holds tremendous potential as a material for developing high voltage and extreme condition power electronic devices due to its remarkable properties such as superior thermal conductivity and large electric field strength along with high carrier mobilities and saturation velocities. However, the absence of a reliable n-type doping method at room temperature has impeded any promising advancements in diamond-based electronics. The issue primarily stems from the donor energy levels being situated deep within the bandgap, which necessitates device operations at higher temperatures for sufficient thermal activation of carriers. Here, we offer an alternate pathway to circumvent this bottleneck by integrating for the first time, atomically thin n-type two-dimensional (2D) monolayers of molybdenum disulfide (MoS₂) acting as a pseudo delta-doped layer with boron doped p-type polycrystalline and single crystal diamond to demonstrate both lateral and vertical 2D/3D heterostructure based p-n junction diodes, respectively, which operate at room temperature. From the measured current-voltage (I-V) curves, our two-terminal devices show an ideality factor value of 6, a rectification ratio (RR) of 10³, a reverse saturation current of 1nA, and a on/off ratio of ~ 10⁸. Moreover, our p-n heterojunction can seamlessly operate at temperatures as high as 573K, without any degradation in the device characteristics due to diamond’s high thermal conductivity, which allows it to serve as a great heat sink. With the help of analytical models, we find that the origin of the current rectification stems from tunnelling assisted interlayer recombination of majority carriers from the metal/2D junction into bulk diamond on application of forward bias voltage. We believe our demonstration can offer fresh insights and provide a holistic platform for the development of highly reliable and efficient diamond-based integrated with low-dimensional materials for power electronics.