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KR-102963904-B1 - p-NiO/i-β-Ga2O3/n-β-Ga2O3 Deep UV photodetector and method of fabricating the same

KR102963904B1KR 102963904 B1KR102963904 B1KR 102963904B1KR-102963904-B1

Abstract

A method for manufacturing a self-powered deep ultraviolet photodetector may include the steps of growing an intrinsic β-gallium oxide epitaxial layer on a doped β-gallium oxide substrate, depositing a nickel oxide layer on the intrinsic β-gallium oxide epitaxial layer by sputtering with a nickel oxide target in an atmosphere of mixed gas of argon and oxygen, depositing a nickel layer on the nickel oxide layer by sputtering with a nickel target in an argon atmosphere, and heat-treating the nickel oxide layer and the nickel layer after depositing the nickel layer.

Inventors

  • 홍정수

Assignees

  • 가천대학교 산학협력단

Dates

Publication Date
20260511
Application Date
20240522

Claims (9)

  1. A step of growing an intrinsic β-gallium oxide epitaxial layer on a doped β-gallium oxide substrate; A step of depositing a nickel oxide layer on the intrinsic β-gallium oxide epitaxial layer by sputtering with a nickel oxide target in a mixed gas atmosphere of argon and oxygen; A step of depositing a nickel layer on the nickel oxide layer by sputtering with a nickel target in an argon atmosphere; The method includes the step of heat-treating the nickel oxide layer and the nickel layer after depositing the nickel layer, A method for manufacturing a self-powered deep ultraviolet photodetector, wherein the Fermi level of the nickel oxide layer is adjusted to increase the internal potential resulting from the junction of the nickel oxide layer and the intrinsic β-gallium oxide epitaxial layer.
  2. A method for manufacturing a self-powered deep ultraviolet photodetector according to claim 1, wherein, in order to control the Fermi level of the nickel oxide layer, the flow rate of the argon in the mixed gas is fixed and the flow rate of the oxygen is controlled between 2 SCCM and 4 SCCM.
  3. A method for manufacturing a self-powered deep ultraviolet photodetector according to claim 1, wherein the flow rate of the argon in the mixed gas is 20 SCCM and the flow rate of the oxygen is 4 SCCM.
  4. A method for manufacturing a self-powered deep ultraviolet photodetector according to claim 1, wherein the doped β-gallium oxide substrate is an n-type semiconductor and the intrinsic β-gallium oxide epitaxial layer is an intrinsic layer.
  5. A method for manufacturing a self-powered deep ultraviolet photodetector according to claim 1, wherein the heat treatment is a rapid heat treatment carried out at 300°C in an oxygen atmosphere for 1 minute.
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Description

Self-powered deep ultraviolet photodetector and method of fabricating the same {p-NiO/i-β-Ga2O3/n-β-Ga2O3 Deep UV photodetector and method of fabricating the same} The present invention relates to a self-powered deep ultraviolet (DUV) photodetector. Ultraviolet radiation can be classified into UV-A, ranging from approximately 320 to 400 nm; UV-B, ranging from approximately 290 to 320 nm; and UV-C, ranging from approximately 200 to 280 nm. In particular, UV-C, also known as DUV (Deep UV), is widely used in various applications such as flame and ozone detection, missile warning, and biological and chemical analysis. To utilize DUV wavelengths, it is important to be able to detect them accurately. Among DUV detection methods, self-powered photodetectors can obtain energy directly from nature, reduce environmental pollution, and operate continuously without external power sources such as batteries. The eco-friendly characteristics of self-powered photodetectors have been extensively studied across various fields. The self-powered nature of a photodetector is primarily influenced by the internal potential. When a photodetector is exposed to ultraviolet light, photogenerated electron-hole pairs separate and move due to the internal potential. Therefore, the higher the internal potential, the faster the responsiveness, current density, and response speed of the photodetector. Various technologies utilizing wide bandgap materials have been applied to fabricate self-powered DUV photodetectors, such as p-n junctions, Schottky contacts, and p-i-n junctions. Hereinafter, the present invention is described with reference to embodiments illustrated in the accompanying drawings. For the sake of understanding, identical reference numerals are assigned to identical components throughout the entire accompanying drawings. The configurations illustrated in the accompanying drawings are merely exemplary embodiments implemented to explain the present invention and are not intended to limit the scope of the invention. In particular, the accompanying drawings depict some components in a somewhat exaggerated manner to aid in understanding the invention. Since the drawings are a means for understanding the invention, it should be understood that the width or thickness of components depicted in the drawings may differ in actual implementation. Meanwhile, throughout the entire detailed description of the invention, identical components are described with reference to identical reference numerals. FIG. 1 is a diagram illustrating an exemplary self-powered deep ultraviolet photodetector. Figure 2a shows the X-ray diffraction (XRD) patterns of unheat-treated nickel oxide and nickel thin films, and Figure 2b shows the XRD patterns of heat-treated nickel oxide and nickel thin films. Figure 3 shows SEM images used to evaluate the surfaces of nickel oxide thin films and nickel thin films. Figure 4a is a graph showing the electrical characteristics of nickel oxide thin films rapidly heat-treated after deposition with different oxygen flow rates, and Figure 4b is a graph showing the optical characteristics. Figures 5a to 5c are graphs showing the optical bandgap energy of nickel oxide thin films rapidly heat-treated after deposition with different oxygen flow rates. FIGS. 6a to 6b are voltage-current graphs of a self-powered deep ultraviolet photodetector having a nickel oxide layer deposited with different oxygen flow rates and then rapidly heat-treated, and FIGS. 6c to 6e are electrical parameter graphs of a self-powered deep ultraviolet photodetector having a nickel oxide layer deposited with different oxygen flow rates and then rapidly heat-treated. FIGS. 7a to 7d are band diagrams of a self-powered deep ultraviolet photodetector having a nickel oxide layer that has been rapidly heat-treated after deposition. FIGS. 8a to 8f are graphs showing the optical characteristics of the first to third photodetectors. FIGS. 9a to 9f are graphs showing the response speeds of the first to third photodetectors. The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having"