Ultrawide-Bandgap p-n Heterojunction of Diamond/β-Ga₂O₃ for a Solar-Blind Photodiode

Abstract

The potential of ultrawide-bandgap (UWBG) semiconductors has not been fully explored because of the difficulty of forming a p-n homojunction. In this study, a mixed-dimensional UWBG p-n heterojunction composed of a p-type diamond substrate and an n-type exfoliated β-Ga2O3 nanolayer has been demonstrated via a van der Waals interaction; this type of structure does not suffer from lattice mismatch. Rectifying current-voltage characteristics with a rectification ratio exceeding 107 were obtained with a high reverse hard breakdown voltage of 135 V. This UWBG p-n heterojunction diode exhibited good thermal stability at elevated temperatures, retaining its high rectification ratio and low reverse leakage current. Excellent photoresponse characteristics, including responsivity (12 A W−1), rejection ratio (8.5 × 103), photo-to-dark-current ratio (3900), and fast response/decay characteristics, were observed from the diamond/β-Ga2O3 p-n heterojunction photodiode, showing no persistent photoconductivity. The mixed-dimensional p-n heterojunction diode based on two UWBG semiconductors (p-type diamond and n-type β-Ga2O3) can be used as a robust building block in next-generation power electronics and solar-blind optoelectronics.

Temperature-dependent device properties of γ-CuI and β-Ga2O3 heterojunctions

“…Figure 2d shows the log plot of the J-V curve at room temperature. The diode characteristics can be compared with the previously reported results for γ-CuI/β-Ga 2 O 3 and diamond/β-Ga 2 O 3 heterojunction diodes [11,20]. The diode ideality factor (n), computed from the log plot, was found to be 3.5.…”

“…β-Ga 2 O 3 exhibits n-type semiconducting behavior due to the presence of oxygen vacancies, similar to many other oxide semiconductors [9]. Most device fabrication approaches have adopted the Schottky junction or p-n heterojunction structure for practical applications [10,11]. Thus, suitable materials for fabricating a Schottky or p-n junction of Ga 2 O 3 are critical in achieving high device performance.…”

A Strategic Review on Gallium Oxide Based Deep‐Ultraviolet Photodetectors: Recent Progress and Future Prospects

“…Kim et al. [ 210 ] have bonded an exfoliated n‐type β‐Ga 2 O 3 nanolayer to a p‐type diamond substrate via a van der Waals interaction. The multidimensional p–n heterojunctions diode based on the two UWBG semiconductors showed a responsivity of 12 A W −1 , a PDCR of 3900 and a response speed of τ r ≈ 0.56 s and τ d ≈ 0.095 s at a reverse bias of −15 V, without any PPC effect.…”

“…The ease of mechanical exfoliation of β-Ga 2 O 3 single crystals has led to the development of van der Waals heterojunctions which has the added advantage of no lattice mismatch and chemical bonding constraints. Kim et al [210] have bonded an exfoliated n-type β-Ga 2 O 3 nanolayer to a p-type diamond substrate via a van der Waals interaction. The multidimensional p-n heterojunctions diode based on the two UWBG semiconductors showed a responsivity of 12 A W −1 , a PDCR of 3900 and a response speed of τ r ≈ 0.56 s and τ d ≈ 0.095 s at a reverse bias of −15 V, without any PPC effect.…”

Investigation of Nano‐Gaps in Fractured β‐Ga2O3 Nanomembranes Formed by Uniaxial Strain

“…[ 18–21 ] Particularly, β‐Ga 2 O 3 NMs offer more freedom for integration with other materials, and various attempts have been made to integrate β‐Ga 2 O 3 NM heterogeneously with other functional materials to obtain unique electrical properties or enhanced optical properties. [ 22–25 ] Furthermore, β‐Ga 2 O 3 NMs open up the new possibilities to realize flexible devices that have the advantages of ultra‐wide bandgap semiconductors, such as a high breakdown electric field, transparency, and solar‐blind photodetection, while still maintaining good mechanical flexibility. In fact, the first flexible electronics based on β‐Ga 2 O 3 NM‐based demonstrated by our group show a stable breakdown electric field over 1 MV cm −1 under bending condition.…”