κ/β‐Ga2O3 Type‐II Phase Heterojunction

• DOI: 10.1002/adma.202406902
• Publication Date: 2025-01-14T06:43:13Z
• Authors: Yi Lu; Patsy A. Miranda ...; Xiao Tang; Zhiyuan Liu; Vishal Khandelwal; Shibin Krishna; Xiaohang Li

Abstract Ultrawide‐bandgap gallium oxide (Ga 2 O 3 ) holds immense potential for crucial applications such as solar‐blind photonics and high‐power electronics. Although several Ga polymorphs, i.e., α, β, γ, δ, ε, κ phases, have been identified, the band alignments between these phases largely overlooked due to epitaxy challenges inadvertent neglect. Despite having similar stoichiometry, heterojunctions involving different may exhibit offsets. Here, β‐Ga /κ‐Ga ‐stacked “phase heterojunction” is demonstrated experimentally. This phase heterojunction has a sharp well‐defined interface, subsequent measurements reveal an unbeknown type‐II alignment with significant valence/conduction offsets of ≈0.65 eV/0.71 eV. promising self‐powered deep ultraviolet (DUV) signal detection, necessitating internal electric field near junction matching absorption properties effective electron–hole separation. The fabricated photodetector displays responsivity three orders magnitude higher at 17.8 mA W −1 , improved response times (rise time ≈0.21 s, decay ≈0.53 s) under DUV illumination without external bias in comparison bare κ‐Ga photodetectors, confirming strong interfacial electrical field. study provides profound insight into /Ga interfaces allowing use advance electronic device applications.