A broad-spectrum UV photodetector with ultrahigh detectivity and rapid response speed has been achieved inβ-Ga_(2)O_(3)/GaN heterojunction,in which,theβ-Ga_(2)O_(3) is synthesized by substituting oxygen for nitrogen...A broad-spectrum UV photodetector with ultrahigh detectivity and rapid response speed has been achieved inβ-Ga_(2)O_(3)/GaN heterojunction,in which,theβ-Ga_(2)O_(3) is synthesized by substituting oxygen for nitrogen in the top layer of the GaN matrix at high temperature.The processes and mechanism of transforming GaN with varying crystal quality into β-Ga_(2)O_(3) at high temperatures were studied in detail.The newly formed oxide layer is a monoclinic β-Ga_(2)O_(3) with(01)preferred orientation.X-ray photoelectron spectroscopy(XPS)and atomic force microscope(AFM)measurements identified oxygen vacancies and surface flatness of β-Ga_(2)O_(3),respectively,which are closely related to the crystal quality of GaN.The oxygen vacancies and the root mean square of morphology roughness of β-Ga_(2)O_(3) decrease with the improvement of the precursor GaN crystal quality.The cross-section transmission electron microscope(TEM)measurements showed that a hexagonal phase GaN_(x)O_(3(1−x)/2)intermediate layer with a thickness of 5 nm exists at the interface region betweenβ-Ga_(2)O_(3) and hexagonal GaN.This indicates a molecular reconfiguration of the hexagonal system to a monoclinic system with oxygen substitution of nitrogen in GaN matrix.The metal-semiconductor-metal(MSM)planar structure device achieved an ultrahigh detection capability(Responsivity=2493.5 A/W,Detectivity>10^(16)Jones).The response time is in the order of milliseconds(τ_(r)=0.27 ms,τ_(d1)/τ_(d2)=0.33 ms/4.3 ms).A self-powered UV optoelectronic rapid response(τ_(r)=5µs,τ_(d1)/τ_(d2)=0.13 ms/2.3 ms)with the responsivity of 0.6 mA/W and the detectivity of 5.3×10^(11)Jones in the solar-blind wavelength region has been observed in the β-Ga_(2)O_(3)/GaN heterojunction without external bias.With a bias of−10 V loading,the response of the photodetector becomes a broad spectrum,covering the UVA-UVC wavelength range,and the photoresponsivity is up to 13.5 A/W.The detectivity reaches a high value of 2.6×10^(15)Jones.展开更多
基金financially supported by National Key Technologies Research and Development Program of China(No.2019YFA0705202)National Natural Science Foundation of China(Nos.62274027,62404039)+3 种基金Open Research Fund of Songshan Lake Materials Laboratory(No.2023SLABFK03)Funding from Jilin Province(No.20220502002GH)Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(No.GZC20230416)Fundamental Research Funds for the Central Universities(No.2412024QD010).
文摘A broad-spectrum UV photodetector with ultrahigh detectivity and rapid response speed has been achieved inβ-Ga_(2)O_(3)/GaN heterojunction,in which,theβ-Ga_(2)O_(3) is synthesized by substituting oxygen for nitrogen in the top layer of the GaN matrix at high temperature.The processes and mechanism of transforming GaN with varying crystal quality into β-Ga_(2)O_(3) at high temperatures were studied in detail.The newly formed oxide layer is a monoclinic β-Ga_(2)O_(3) with(01)preferred orientation.X-ray photoelectron spectroscopy(XPS)and atomic force microscope(AFM)measurements identified oxygen vacancies and surface flatness of β-Ga_(2)O_(3),respectively,which are closely related to the crystal quality of GaN.The oxygen vacancies and the root mean square of morphology roughness of β-Ga_(2)O_(3) decrease with the improvement of the precursor GaN crystal quality.The cross-section transmission electron microscope(TEM)measurements showed that a hexagonal phase GaN_(x)O_(3(1−x)/2)intermediate layer with a thickness of 5 nm exists at the interface region betweenβ-Ga_(2)O_(3) and hexagonal GaN.This indicates a molecular reconfiguration of the hexagonal system to a monoclinic system with oxygen substitution of nitrogen in GaN matrix.The metal-semiconductor-metal(MSM)planar structure device achieved an ultrahigh detection capability(Responsivity=2493.5 A/W,Detectivity>10^(16)Jones).The response time is in the order of milliseconds(τ_(r)=0.27 ms,τ_(d1)/τ_(d2)=0.33 ms/4.3 ms).A self-powered UV optoelectronic rapid response(τ_(r)=5µs,τ_(d1)/τ_(d2)=0.13 ms/2.3 ms)with the responsivity of 0.6 mA/W and the detectivity of 5.3×10^(11)Jones in the solar-blind wavelength region has been observed in the β-Ga_(2)O_(3)/GaN heterojunction without external bias.With a bias of−10 V loading,the response of the photodetector becomes a broad spectrum,covering the UVA-UVC wavelength range,and the photoresponsivity is up to 13.5 A/W.The detectivity reaches a high value of 2.6×10^(15)Jones.
