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

Abstract

Mixed-dimensional heterostructures are emerging to be very promising for the 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 ~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.

Ultra-violet and yellow-green emissions under intriguing bidirectional DC driving based on Au/i-Ga2O3/n-GaN MIS heterojunction light-emitting diodes

“…The O atoms on the β-Ga 2 O 3 (2̄01) plane can be attached to the Ga atoms on the GaN (002) plane by van der Waals force. 35,36 Moreover, this arrangement of GaN and β-Ga 2 O 3 can be further confirmed by the XRD analysis, that is, β-Ga 2 O 3 (2̄01) is parallel to GaN (002) in XRD analysis. 14 According to our above-mentioned results, the lattice mismatch between β-Ga 2 O 3 (2̄01) and GaN (002) is as low as 4.81%, which is obtained by ( d 1 − d 2 )/ d 1 , implying that β-Ga 2 O 3 can be easily prepared on the (002) plane of the GaN substrate.…”

A nanoflower-like GaSe/β-Ga2O3 based heterostructure for highly efficient self-powered broadband photodetectors

“…Therefore, the rise and decay times are better for 355 nm, 532 nm, and 625 nm than for 266 nm illumination. 32,51…”

“…31 Among these, GaSe is a semiconducting material with a direct bandgap of 2 eV in its multilayered form. 32,33 GaSe possesses a very low dark current due to its extremely resistant layered structure and poor Hall mobility of the charge carrier, which is essential for applications in photodetectors. 34 In addition, its good thermal stability and absence of dangling bonds make it a prime candidate for use in photodetection.…”

High Performance of Zero-Power-Consumption MOCVD-Grown β-Ga2O3-Based Solar-Blind Photodetectors with Ultralow Dark Current and High-Temperature Functionalities

“…In conclusion, ultra-high-performance DUV PDs based on UID MOCVD-grown β-Ga 2 O 3 were fabricated, and the gain and the self-powered behavior were thoroughly investigated. The fabricated DUV PDs exhibited high responsivity of 6.80 A/W at 10 V with ultralow dark current of 1.75 fA at zero bias and 254 pA at 10 V. The PDs showed high PDCR > 10 3 , NEP < 10 −14 W/Hz 1/2 , and detectivity > 10 11 Jones at zero bias and PDCR > 10 5 , NEP < 10 −16 W/Hz 1/2 , and detectivity > 10 14 Jones at higher biases, with high photosensitivity > 10 10 cm 2 / W, implying the ability of PDs to detect extremely weak signals from background noise. The high-temperature stability of DUV PDs on films up to 125 °C was demonstrated.…”

“…Deep ultraviolet photodetectors (DUV PDs) (<280 nm), also known as solar-blind PDs, have piqued interest due to their wide range of applications in defense, space communication, civil, agriculture, healthcare, UV astronomy, high-temperature flame detection, solar-blind imaging for missile tracking, ozone hole monitoring, and other fields. − Wide-band-gap and ultrawide-band-gap semiconductor materials such as GaN, AlGaN, diamond, Lu 2 O 3 , and Ga 2 O 3 have emerged as promising candidates for solar-blind PDs because of their wide- and ultrawide band gap due to which they exhibit intrinsic solar-blindness. Unlike commercially available UV PDs based on narrow-band-gap semiconductor materials such as Si and GaAs, they do not require any additional optical filter or large cooling systems. ,− Among these, β-Ga 2 O 3 has received a lot of attention because of its excellent material properties such as an ultrawide direct band gap of about 4.9 eV, superior radiation hardness, high chemical and thermal stability, and high absorption coefficient (>10 5 cm –1 ). In addition, to date, high-crystalline-quality Ga 2 O 3 single-crystal substrates, epilayers, and thin films could be grown quite maturely and cost-effectively by various melt growth and thin-film techniques including edge-defined film-fed growth (EFG), Czochralski (CZ) method, MOCVD, halide vapor-phase epitaxy (HVPE), atomic layer deposition (ALD), pulsed laser deposition (PLD), and molecular beam epitaxy (MBE) without any doping complexity in comparison to other wide and ultrawide-band-gap semiconductor materials. − Apart from the β-phase, DUV PDs have also been demonstrated on amorphous and ε-phases of Ga 2 O 3 . ,,− …”