Thermal oxidation of AlGaN nanowires for sub-250 nm deep ultraviolet photodetection

Abstract

In this work, we demonstrated a thermal oxidation process for AlGaN nanowires and revealed the underlying mechanism of AlGaN to AlGaO transition for sub-250 nm deep ultraviolet photodetection. When the AlGaN nanowires were exposed to oxygen atmosphere below a temperature of 700 °C, only the Al–N bond was oxidized while the Ga–N bond remained intact, and thereafter, the AlGaN nanowires were slowly oxidized to AlGaON complex. However, as the oxidation temperature was elevated to above 700 °C, the AlGaN complex was transformed into AlGaO complex. Using this method, photodetectors based on AlGaON nanowires were fabricated and compared with its AlGaN counterpart. The AlGaON photodetector showed a response peak at deep ultraviolet of 242 nm with a high responsivity of 726 mA W−1, compared with the response peak at 276 nm in AlGaN nanowires. This work offers an alternative method towards the realization of high performance sub-250 nm deep ultraviolet photodetection.

Recent advances in the growth of gallium oxide thin films employing various growth techniques—a review

“…Similar to gallium nitride (GaN) and silicon carbide (SiC) semiconductors [1][2][3][4], gallium oxide (Ga2O3) is being pursued as a viable alternative material for several applications due to its large bandgap, extremely high Baliga figure of merit (BFOM) and relatively inert nature. Moreover, the Ga2O3 possesses six polymorphs α, β, γ, δ, ε, and κ depending on the growth conditions [5][6][7][8][9][10][11].…”

Ultrahigh Detectivity Broad Spectrum UV Photodetector with Rapid Response Speed Based on p‐β Ga2O3/n‐GaN Heterojunction Fabricated by a Reversed Substitution Doping Method

“…Utilizing strong light absorption of the intrinsic forbidden band between the valence and conduction bands, UV PDs based on several kinds of wide-bandgap semiconductors, including Al x Ga 1−x N/GaN, MgZnO/ ZnO, and SiC, have been explored. [5][6][7][8][9][10][11][12] Among these materials, the III-V nitride semiconductors are ideal for UV PD applications, which have large direct bandgaps spanning a range of bandgap energies of 0.7-6.2 eV, obtained by tuning the mole fraction in Ga x In 1−x N or Al x Ga 1−x N alloying processes. Enormous efforts have been made to improve the photoconductors or junction UV PDs based on nitride semiconductors.…”

High-performance shortwave deep-UV response-enhanced photodetector based on nanoporous AlGaO/AlGaN with efficient light-harvesting

“…However, the limited exposure area to oxygen in the planar structure seriously hinders its oxidation process as illustrated in the EDS results. Since a large amount of N remaining on the surface formed the AlGaON structure, 38 the bandgap might merely be slightly widened. Conversely, with the large porosity and surface-to-volume ratio introduced by the NP-structure, the oxidation efficiency was significantly improved in both surface and interior exposing to O 2 , resulting in a high O content that far exceeds that of N, as shown in Fig.…”