In this colloquium, I will give a talk on all-graphene vertical tunneling junctions that were fabricated by chemical vapor deposition and chemical treatment. One of the most important characteristics of the graphene tunneling junctions is the asymmetric rectifying behavior showing on/off ratio of 103 under bias voltages below ± 10 V without gating, which may be useful for practical device applications. The observed rectification results from the strongly-corrugated insulating or semiconducting interlayers or graphene quantum dots (GQDs) sandwiched between the doped or pristine graphene sheets, which is actually a structure like metal-insulator-metal or metal-semiconductor-metal diode. The I-V measurements at low temperatures demonstrate that the vertical junctions act as tunneling diodes, showing negative differential resistance in a voltage region under forward bias. Recently, there have been several studies on graphene-based photodetectors (PDs) due to the potential applications to transparent and flexible photonics, but their performance is far below the standards of commercially-available PDs. Most of the studied graphene-based PDs are based on field effect transistor structures containing lateral-type graphene p-n or graphene-metal junctions and heterostructures, not suitable for practical large-scale device applications because all of them were made of mechanical graphene. I also discuss high-efficient PD behaviors of the all-graphene vertical tunneling diodes. The observed unique PD characteristics well follow what are expected from its band structure and the tunneling of current through the interlayer or GQDs between the metallic graphene layers. High detectivity (1012 cm Hz1/2 W−1) and responsivity (0.4  1.0 A/W) are achieved in the broad spectral range from ultraviolet to near-infrared and the photoresponse has been almost consistent under six month-operations. The high PD performance of the all-graphene vertical tunneling diodes can be understood by the high photocurrent gain and the carrier multiplication arising from impact ionization in graphene.