Investigation of a vertical 2D/3D semiconductor heterostructure based on GaSe and Ga2O3

Mixed-dimensional heterostructures are emerging to be very promising for future electronic and optoelectronic applications. Here, we report on the fabrication and characterization of a 2D/3D vertical van der Waals p-n heterojunction based on p-type gallium selenide (GaSe) and n-type gallium oxide (Ga2O3). Kelvin Probe Force Microscopic (KPFM) measurements have been conducted to estimate the difference in the surface potential values between GaSe and Ga2O3, which is further used to find out the conduction band offset value at the GaSe/Ga2O3 hetero-interface to design the band diagrams. The current-voltage measurements on the device display a diode-like behavior which is attributed to the type-II band alignment, present at the p-n junction interface as per the electron affinities and bandgap values of GaSe and Ga2O3. The device exhibits a high current rectification ratio of similar to 2500 extracted at +/- 5 V. The photoresponse properties of the heterostructure are also studied and the figure of merit parameters of the photodetector such as photoresponsivity and specific detectivity have been evaluated for the fabricated device. Since the GaSe/Ga2O3 heterojunction holds a great potential in the field of efficient optoelectronic devices, we believe our study could pave the way to designing innovative optoelectronic devices by integrating low-dimensional materials with conventional 3D semiconducting materials.

Automated summary

In this study, a 2D/3D vertical van der Waals p-n heterojunction based on p-type gallium selenide (GaSe) and n-type gallium oxide (Ga2O3) is fabricated and characterized. The conduction band offset at the GaSe/Ga2O3 hetero-interface is estimated using Kelvin Probe Force Microscopic (KPFM) measurements, and the band diagrams are designed accordingly. The diode-like behavior observed in the current-voltage measurements is attributed to the type-II band alignment at the p-n junction interface. The heterostructure exhibits high current rectification ratio and promising photoresponse properties, making it a potential candidate for efficient optoelectronic devices.