US-12628441-B2 - Quantum detector with vertically stacked structure

US12628441B2US 12628441 B2US12628441 B2US 12628441B2US-12628441-B2

Abstract

A quantum detector is provided with a vertically stacked structure. The detector comprises a conductive substrate, a plurality of quantum detectors configured on the conductive substrate, and a lower electrode. Each of the quantum detectors comprises an electron transport layer (GaAs), a three-dimensional topological insulator layer (Sb-doping Bi 2 Te 3 ), a light-absorbing layer (e.g. having excellent graphene quantum dot (ZnO)), and an upper electrode. The lower electrode is disposed between first and second upper electrodes of the first and second quantum detectors that are adjacent to each other to provide a vertical series of electrical coupling. Thus, the present invention provides a novel photodetector with a vertical structure. With the preparation of a topological material through high-power impulsed magnetron sputtering (having a special surface state of an extremely-low energy gap), the mobility of electron-hole-pair carriers is effectively improved. The whole device achieves low energy consumption and extended use life.

Inventors

Po-Wen Chen
JIUN-SHEN CHEN
I-Lin Ho
Chi-Tsu Yuan

Assignees

NATIONAL ATOMIC RESEARCH INSTITUTE

Dates

Publication Date: 20260512
Application Date: 20240118
Priority Date: 20231013

Claims (9)

1 . A quantum detector with a vertically stacked structure, comprising: a conductive substrate; a plurality of quantum detectors configured on said conductive substrate, wherein each of said quantum detectors comprises an electron transport layer configured on said conductive substrate; a three-dimensional (3D) topological insulator layer obtained through high-power impulse magnetron sputtering (HiPIMS) and configured on said electron transport layer; an absorbing layer configured on said 3D topological insulator layer; and an upper electrode configured on said absorbing layer; and a lower electrode configured on said conductive substrate, wherein said lower electrode is configured between a first and a second ones of said upper electrodes of a first and second ones of said quantum detectors that are adjacent to each other to provide parallel connections of electrical coupling.
2 . The quantum detector according to claim 1 , wherein said conductive substrate is a transparent conductive glass coated with an indium tin oxide (ITO) film.
3 . The quantum detector according to claim 1 , wherein said electron transport layer is of a photosensitive material.
4 . The quantum detector according to claim 3 , wherein said photosensitive material is gallium arsenide (GaAs) made into said electron transport layer through metal-organic chemical vapor deposition (MOCVD).
5 . The quantum detector according to claim 1 , wherein said 3D topological insulator layer is of a photosensitive material.
6 . The quantum detector according to claim 5 , wherein said photosensitive material is bismuth telluride doped with antimony (S b -doping Bi 2 Te 3 ) to be made into said 3D topological insulator layer through HiPIMS, and has a surface state of an extremely low energy gap.
7 . The quantum detector according to claim 1 , wherein said HiPIMS has an operating condition comprising a frequency of 100˜350 kilo-hertz (kHz), a power of 20˜50 watts (W), an air pressure of 3×10 −3 ˜2×10 −2 Torr, and a temperature of 150˜220 degrees Celsius (° C.).
8 . The quantum detector according to claim 1 , wherein said absorbing layer is of a material selected from a group consisting of graphene quantum dot and molybdenum disulfide (MoS 2 ) quantum dot.
9 . The quantum detector according to claim 8 , wherein said graphene quantum dot is of zinc oxide (ZnO) made into graphene ZnO quantum dot through chemical synthesis.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to quantum detector; more particularly, to a photodetector (PD) with a vertical structure, where, by being fabricated through high-power pulsed magnetron sputtering (HiPIMS), a topological material (having a special surface state of an extremely low energy gap (Eg)) is effectively improved in the mobility of electron-hole-pair carriers; and the whole device achieves low energy consumption and extended use life. DESCRIPTION OF THE RELATED ARTS In recent years, optical detector technology has been widely used in optical imaging, Internet-of-Things communication, biomedicine, and other fields, which plays an important role in promoting the development of related applications of national defense and people's livelihood. Currently, commercialized PDs are mainly composed of inorganic semiconductor materials such as silicon (Si) substrates, germanium (Ge) substrates, indium gallium arsenide (InGaAs), and mercury cadmium telluride (HgCdTe). However, these materials have insufficient detection capabilities in weak light and infrared light bands, where multi-layer stacking is required for amplifying optical signals. This results in limitations, like complex manufacturing procedure, increased process difficulty, and expensive equipment, to the development of these materials. The detection capabilities of traditional semiconductor materials are mainly limited in photosensitive materials, which can only cover a certain waveband area. Especially in the areas of mid-far infrared and megahertz bands, there is a lack of novel and efficient photosensitive materials. The three-dimensional (3D) topological insulator was experimentally confirmed in 2020 at the first time that, owing to its topological surface state of an extremely low Eg, an extremely wide absorption-band capability and an ultra-high drift rate were obtained and the operation with low energy consumption was possible. A quantum detector composing the topological insulators can be used in applications of wide spectrum, from visible light to megahertz bands, for broad prospects. However, as far as the current manufacturing process is concerned, most of the mass production technologies of PD manufacturers still use molecular beam epitaxy equipment to produce 3D topological materials, resulting in high production costs and inability of effective mass-production. Moreover, due to the especially high dark current of conventional PD, the detection capability is poor and it is difficult to distinguish the current response. Even with light illumination, the current difference is very small and, thus, the ability of accurately measuring low-intensity light is limited. Hence, the prior arts do not fulfill all user's requests on actual use. SUMMARY OF THE INVENTION The main purpose of the present invention is to stacking a total current with a vertically-structured currents connected in series, where, on being shone by light, a larger current is generated and dark current is reduced to improve sensitivity to light and responsibility to light source; and, according to the novel structure, the ability of accurately measuring low-intensity light is improved for the whole device. Another purpose of the present invention is to fabricating a 3D topological insulator layer through low-cost HiPIMS, where no thermal annealing is required and, therefore, the overall process is fast. To achieve the above purposes, the present invention is a quantum detector with a vertically stacked structure, comprising a conductive substrate, a plurality of quantum detectors set on the conductive substrate, and a lower electrode set on the conductive substrate, where each of the quantum detectors comprises an electron transport layer set on the conductive substrate, a 3D topological insulator layer obtained through HiPIMS and configured on the electron transport layer, an absorbing layer configured on the 3D topological insulator layer, and an upper electrode configured on the absorbing layer; and the lower electrode is configured between a first and a second ones of the upper electrodes of a first and second ones of the quantum detectors that are adjacent to each other to provide parallel connections of electrical coupling. Accordingly, a novel quantum detector with a vertically stacked structure is obtained. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood from the following detailed description of the preferred embodiment according to the present invention, taken in conjunction with the accompanying drawings, in which FIG. 1 is the perspective view showing the preferred embodiment according to the present invention; FIG. 2 is the view showing the A-A cross section of FIG. 1; and FIG. 3 is the view showing the parallelly-connected currents totaled through the vertically stacked structure. DESCRIPTION OF THE PREFERRED EMBODIMENT The following description of the preferred embodiment is provided to underst