Single-photon light-emitting element and light-emitting device

Abstract

The present invention discloses a single-photon light-emitting element and a light-emitting device. The single-photon light-emitting element includes a stacked structure, a source electrode and a drain electrode, and an external drive circuit. The source electrode and the drain electrode are respectively disposed on opposite sides of the stacked structure. The stacked structure includes a single-electron transistor serving as an electron source or a single-hole transistor serving as a hole source, a tunneling layer, and a recombination region. The external drive circuit is configured to output a drive signal. According to the drive signal, a single electron in the single-electron transistor and / or a single hole in the single-hole transistor recombine in the recombination region to emit a single photon, and the recombination region is a quantum dot, an undoped direct-bandgap semiconductor layer, or an anti-state doped region carrier pool.

Description

Technical Field

[0001] The present invention relates to a single photon emission device (SPED), and more particularly to a single photon emission device and a light emitting device formed in the form of a single exciton device (SED). Background Art

[0002] Quantum communication is one of the main research and application directions of quantum technology. The most ideal quantum communication light source is a single photon source. To achieve single photon emission, it is necessary to be able to "individually" manipulate a specific two-level system so that only one photon is generated under each external trigger. At present, the key single photon gun candidate systems under research include semiconductor quantum dots, mesoscopic quantum wells, single molecule luminescence, single atom luminescence, and color center luminescence in diamonds, etc.

[0003] However, at present, a practical, controllable, and electrically excited single photon source has not been successfully developed. Summary of the Invention

[0004] The present invention provides a single photon emission device that can achieve a controllable single photon source.

[0005] The present invention further provides a light emitting device that can suppress unnecessary spontaneous emission and enhance the required spontaneous emission.

[0006] A single photon emission device of the present invention includes: a stacked structure, a source electrode and a drain electrode, and an external drive circuit. The source electrode and the drain electrode are respectively disposed on opposite sides of the stacked structure. The stacked structure includes: a single electron quantum dot, a first tunneling layer, a single electron gate structure, a single hole quantum dot, a second tunneling layer, and a single hole gate structure. The first tunneling layer completely covers the single electron quantum dot, and the single electron gate structure completely surrounds the single electron quantum dot and is isolated from the single electron quantum dot through the first tunneling layer. The single hole quantum dot is adjacent to the single electron quantum dot. The second tunneling layer completely covers the single hole quantum dot, and the single hole gate structure completely surrounds the single hole quantum dot and is isolated from the single hole quantum dot through the second tunneling layer. The external drive circuit is configured to output a drive signal. According to the drive signal, it controls the single electron tunneling injection of the single electron quantum dot into the single hole quantum dot so that electron-hole recombination occurs in the single hole quantum dot to emit a single photon; or controls the single hole tunneling injection of the single hole quantum dot into the single electron quantum dot so that electron-hole recombination occurs in the single electron quantum dot to emit a single photon.

[0007] In an embodiment of the present invention, the number of the single - electron quantum dots is plural, the number of the single - hole quantum dots is one, and the plural single - electron quantum dots and the single single - hole quantum dot are stacked on top of each other.

[0008] In an embodiment of the present invention, the number of the single - electron quantum dots is one, the number of the single - hole quantum dots is plural, and the single single - electron quantum dot and the plural single - hole quantum dots are stacked on top of each other.

[0009] In an embodiment of the present invention, the number of the single - electron quantum dots is plural, the number of the single - hole quantum dots is plural, and the plural single - electron quantum dots and the plural single - hole quantum dots are horizontally adjacent to each other.

[0010] In an embodiment of the present invention, the number of the single - electron quantum dots is plural, the number of the single - hole quantum dots is plural, and the plural single - electron quantum dots and the plural single - hole quantum dots are arranged in pairs vertically.

[0011] Another single - photon emitting device of the present invention includes: a stacked structure, a source electrode and a drain electrode, and an external driving circuit. The source electrode and the drain electrode are respectively disposed on opposite sides of the stacked structure. The stacked structure includes: a single - electron quantum dot, a first tunneling layer, a single - electron gate structure, a single - hole quantum dot, a second tunneling layer, a single - hole gate structure, and an undoped direct - bandgap semiconductor layer. The first tunneling layer completely covers the single - electron quantum dot, and the single - electron gate structure completely surrounds the single - electron quantum dot and is isolated from the single - electron quantum dot through the first tunneling layer. The second tunneling layer completely covers the single - hole quantum dot, and the single - hole gate structure completely surrounds the single - hole quantum dot and is isolated from the single - hole quantum dot through the second tunneling layer. The undoped direct - bandgap semiconductor layer is between the single - electron quantum dot and the single - hole quantum dot and is isolated from the single - electron quantum dot and the single - hole quantum dot respectively through the first and second tunneling layers. The external driving circuit is configured to output a driving signal, and according to the driving signal, control the tunneling injection of the single electron of the single - electron quantum dot and the single hole of the single - hole quantum dot into the undoped direct - bandgap semiconductor layer, so that electrons and holes recombine in the undoped direct - bandgap semiconductor layer to emit a single photon.

[0012] In another embodiment of the present invention, the single - photon emitting device may further include a control gate structure and an insulating layer. The control gate structure completely surrounds the undoped direct - bandgap semiconductor layer, and the insulating layer is located between the control gate structure and the undoped direct - bandgap semiconductor layer.

[0013] In another embodiment of the present invention, the undoped direct bandgap semiconductor layer is a quantum dot layer or a quantum well layer.

[0014] In the above embodiments of the present invention, the single electron quantum dot and the single hole quantum dot may be of the same material or different materials.

[0015] Another single photon emitting device of the present invention includes: a stacked structure, a source electrode and a drain electrode, and an external drive circuit. The source electrode and the drain electrode are respectively disposed on opposite sides of the stacked structure. The stacked structure includes: a quantum dot, a tunneling layer, a control gate structure, and an anti-state doped region carrier pool. The quantum dot is a single electron quantum dot or a single hole quantum dot, and the tunneling layer completely covers the quantum dot. The control gate structure completely surrounds the quantum dot and is isolated from the quantum dot through the tunneling layer. The anti-state doped region carrier pool is adjacent to the quantum dot and has a conductivity state opposite to that of the quantum dot, and is isolated from the quantum dot through the tunneling layer. The external drive circuit is configured to output a drive signal, and according to the drive signal, control the tunneling injection of single electrons or single holes of the quantum dot into the anti-state doped region carrier pool, so that electrons and holes recombine in the anti-state doped region carrier pool to emit a single photon.

[0016] In yet another embodiment of the present invention, the quantum dot is a single electron quantum dot, and the anti-state doped region carrier pool is a P-type carrier pool.

[0017] In yet another embodiment of the present invention, the quantum dot is a single hole quantum dot, and the anti-state doped region carrier pool is an N-type carrier pool.

[0018] In yet another embodiment of the present invention, the anti-state doped region carrier pool is a one-dimensional or two-dimensional or three-dimensional semiconductor structure.

[0019] In yet another embodiment of the present invention, the one-dimensional semiconductor structure includes a nanowire, the two-dimensional semiconductor structure includes a quantum well, and the three-dimensional semiconductor structure includes a bulk.

[0020] In various embodiments of the present invention, the single electron quantum dot is an N-type direct bandgap semiconductor quantum dot or a metal quantum dot.

[0021] In various embodiments of the present invention, the single hole quantum dot is a P-type direct bandgap semiconductor quantum dot.

[0022] Yet another light emitting device of the present invention includes: a structure having an optical resonance cavity and the above single photon emitting device, and the single photon emitting device is disposed within the structure having the optical resonance cavity.

[0023] In another embodiment of the present invention, the above-mentioned structure with an optical resonator includes a micropillar structure, a photonic crystal structure, or a microdisk structure.

[0024] In another embodiment of the present invention, the above-mentioned light-emitting device may further include an external cavity of a distributed Bragg reflector (DBR) for condensing light.

[0025] Based on the above, the present invention achieves a mechanism for controlling single-photon emission through a quantum dot structure of a single-electron transistor (SET) or a single-hole transistor (SHT), in combination with an external circuit. Moreover, the electron-hole recombination center of the single-photon light-emitting element of the present invention can be controlled within a preset region, so it is expected to achieve single-photon emission. In addition, the single-photon light-emitting element of the present invention is disposed within a structure having an optical resonator, so the emission efficiency of the quantum dots can be significantly improved.

[0026] To make the above features and advantages of the present invention more obvious and understandable, specific embodiments are hereinafter given, and detailed descriptions are made in conjunction with the accompanying drawings as follows. Description of the Drawings

[0027] Figure 1 is an exploded view of a single-photon light-emitting element according to a first embodiment of the present invention;

[0028] Figure 2 is Figure 1 the energy band diagram of the single-photon light-emitting element;

[0029] Figure 3 is Figure 1 the equivalent circuit diagram of the single-photon light-emitting element;

[0030] Figure 4A is an exploded view of a single-photon light-emitting element according to another example of the first embodiment;

[0031] Figure 4B is Figure 4A the equivalent circuit diagram of the single-photon light-emitting element;

[0032] Figure 4C is an exploded view of a single-photon light-emitting element according to yet another example of the first embodiment;

[0033] Figure 4D is an exploded view of a single-photon light-emitting element according to still another example of the first embodiment;

[0034] Figure 5 is an exploded view of a single-photon light-emitting element according to a second embodiment of the present invention;

[0035] Figure 6 is Figure 5Equivalent circuit diagram of a single-photon light-emitting element;

[0036] Figure 7 Schematic exploded view of a single-photon light-emitting element of another example of the second embodiment;

[0037] Figure 8 Schematic exploded view of a single-photon light-emitting element of the third embodiment of the present invention;

[0038] Figure 9 Schematic exploded view of a light-emitting device of the fourth embodiment of the present invention.

[0039] Symbol description

[0040] 10, 10’, 10”, 10″′, 50, 50’, 80, SPED: Single-photon light-emitting element

[0041] 90: Light-emitting device

[0042] 100, 500, 800: Stacked structure

[0043] 102a: Source electrode

[0044] 102b: Drain electrode

[0045] 104: External drive circuit

[0046] 106: Single-electron quantum dot

[0047] 108: First tunneling layer

[0048] 110: Single-electron gate structure

[0049] 112: Single-hole quantum dot

[0050] 114: Second tunneling layer

[0051] 116: Single-hole gate structure

[0052] 502, i: Undoped direct bandgap semiconductor layer

[0053] 504, 806: Control gate structure

[0054] 506: Insulating layer

[0055] 802: Quantum dot

[0056] 804: Tunneling layer

[0057] 808: Inverted carrier pool

[0058] 900: Structure with an optical resonator

[0059] C_spacer, C1_spacer, C2_spacer, C3_spacer, Cn_spacer: Capacitance generated by the tunneling layer between SET and SHT

[0060] C_SET_spacer: Capacitance generated by the tunneling layer between SET and the undoped direct bandgap semiconductor layer

[0061] C_SHT_spacer: Capacitance generated by the tunneling layer between SHT and the undoped direct bandgap semiconductor layer

[0062] Cd_SHT: Capacitance generated by the tunneling layer between SHT and the drain

[0063] Cg_SET, Cg_SET1, Cg_SET2, Cg_SET3, Cg_SETn: Capacitance generated by the tunneling layer between SET and the single electron gate structure

[0064] Cg_SHT: Capacitance generated by the tunneling layer between SHT and the single hole gate structure

[0065] Cs_SET, Cs_SET1, Cs_SET2, Cs_SET3, Cs_SETn: Capacitance generated by the tunneling layer between SET and the source

[0066] SET, SET#1, SET#2, SET#3, SET#n: Positions of single electron quantum dots

[0067] SHT: Position of single hole quantum dot

[0068] Vd: Drain voltage

[0069] Vg_SET, Vg_SET1, Vg_SET2, Vg_SET3, Vg_SETn: Single electron gate voltages

[0070] Vg_SHT: Single hole gate voltage

[0071] Vs, Vs1, Vs2, Vs3, Vsn: Source voltages Detailed implementation manners

[0072] Examples are listed below and described in detail in conjunction with the accompanying drawings. However, the provided examples are not intended to limit the scope covered by the present invention. In addition, the drawings are for illustrative purposes only and are not drawn to the original size. For ease of understanding, the same elements in the following description will be denoted by the same reference numerals.

[0073] In addition, terms such as "include", "comprise", "have", etc. used herein are open-ended terms, that is, they mean "including but not limited to".

[0074] It should be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Thus, the "first element", "component", "region", "layer", or "part" discussed below may be referred to as a second element, component, region, layer, or part without departing from the teachings herein.

[0075] In addition, the directional terms mentioned in the text, such as "up", "down", etc., are only used to refer to the direction of the accompanying drawings and do not limit the present invention.

[0076] Figure 1 is an exploded view of a single-photon emitting element according to a first embodiment of the present invention.

[0077] Please refer to Figure 1 , a single-photon emitting element 10 includes: a stacked structure 100, a source electrode 102a and a drain electrode 102b, and an external drive circuit 104. The source electrode 102a and the drain electrode 102b are respectively disposed on opposite sides of the stacked structure 100. It should be noted that although the exploded structural views attached to the specification are all represented in the shape of a cylinder or a disk, they are only used to express the relative positions in space and do not limit the actual shape of the single-photon emitting element of the present invention, and the placement in the vertical, horizontal, or other directions is not restricted. The stacked structure 100 in the first embodiment includes a single electron quantum dot 106, a first tunneling layer 108, a single electron gate structure 110, a single hole quantum dot 112, a second tunneling layer 114, and a single hole gate structure 116. The first tunneling layer 108 completely coats the single electron quantum dot 106, and the single electron gate structure 110 completely surrounds the single electron quantum dot 106 and passes through the first tunneling layer 108, being isolated from the single electron quantum dot 106. The single hole quantum dot 112 is adjacent to the single electron quantum dot 106, the second tunneling layer 114 completely coats the single hole quantum dot 112, and the single hole gate structure 116 completely surrounds the single hole quantum dot 112 and passes through the second tunneling layer 114, being isolated from the single hole quantum dot 112. Thus, the single-photon emitting element 10 of the present invention is a gate-all-around (GAA) structure, and tunneling through a very thin insulating layer is required on the carrier transport path. For example, the thickness of the first tunneling layer 108 and the thickness of the second tunneling layer 114 are each about Hereinafter, as to thickness.

[0078] The external drive circuit 104 is configured to output a drive signal. According to the drive signal, the single-electron tunneling of the single-electron quantum dot 106 is controlled to inject into the single-hole quantum dot 112, so that electron-hole pairs recombine in the single-hole quantum dot 112 to emit single photons; or, the single-hole tunneling of the single-hole quantum dot 112 is controlled to inject into the single-electron quantum dot 106, so that electron-hole pairs recombine in the single-electron quantum dot 106 to emit single photons.

[0079] In this embodiment, the single-hole quantum dot 112 is used as a hole source, and the single-electron transistor (SET) is used as an electron source to tunnel the single electron into the single-hole quantum dot 112; or vice versa, the single-electron quantum dot 106 is used as an electron source, and the single-hole transistor (SHT) is used as a hole source to tunnel the single hole into the single-electron quantum dot 106, so that electron-hole pairs recombine to emit single photons, and the recombination center is in one of the single-hole quantum dot 112 and the single-electron quantum dot 106.

[0080] The so-called SET here is a quantum dot covered by an insulating layer (the first tunneling layer 108), which has a quantum confinement effect and is called the central island (the single-electron quantum dot 106). The quantum dot of the SET is an n-type direct-bandgap semiconductor. Electrically, the SET is a three-terminal device: carriers tunnel from the source electrode 102a into the central island, and then tunnel out of the central island into the drain electrode 102b, and the potential of the central island is controlled by the control gate (the single-electron gate structure 110).

[0081] The so-called SHT here is a quantum dot covered by an insulating layer (the second tunneling layer 114), which also has a quantum confinement effect and is called the central island (the single-hole quantum dot 112). The central island of the quantum dot of the SHT is a P-type direct-bandgap semiconductor quantum dot. Electrically, the SHT is a three-terminal device: carriers tunnel from the source electrode 102a into the central island, and then tunnel out of the central island into the drain electrode 102b, and the potential of the central island is controlled by the control gate (the single-hole gate structure 116).

[0082] Theoretically, the calibration of the single-photon signal source is described by using the second-order intensity correlation coefficient of the optical field:

[0083]

[0084] where I(t) is the function of the optical field intensity varying with time.

[0085] An ideal single-photon source emits only one photon each time, and the probability of two photons arriving simultaneously is zero, i.e., g (2) (0)=0. In the present invention, the signal of the external drive circuit 104 can be used to control the opening or closing of the circuit to adjust the potential of SET / SHT in the single-photon emitting element 10, so as to determine the emission frequency of single photons.

[0086] The mode of the single-photon emitting element 10 is such an artificial single exciton diode (SED) structure. The traditional definition of an exciton is associated by the Coulomb force between an electron and a hole; as for the single electron-single hole quantum dot light-emitting element of the first embodiment, the correlation of the composite-emitted photons is controlled (switching speed) by the external drive circuit 104 through the above control gate, so it can also be regarded as a single exciton transistor. Through the natural quantum dot structure of SET or SHT, the high density of states (DOS) improves the internal quantum efficiency (IQE) to reduce non-radiative recombination. In short, the structure and function of the single-photon emitting element 10 are single electron-single hole quantum dot light-emitting elements.

[0087] In this embodiment, the single electron quantum dot 106 and the single hole quantum dot 112 can be of the same material or different materials. If the single electron quantum dot 106 and the single hole quantum dot 112 are of the same material, the single-photon emitting element 10 can be regarded as a homogeneous single exciton element (Homogeneous SED), for example, both the single electron quantum dot 106 and the single hole quantum dot 112 are GaAs; if the single electron quantum dot 106 and the single hole quantum dot 112 are of different materials, the single-photon emitting element 10 can be regarded as a heterogeneous single exciton element (Heterogeneous SED), for example, the single electron quantum dot 106 is silicon and the single hole quantum dot 112 is GaAs; the single electron quantum dot 106 is SiGe and the single hole quantum dot 112 is GaAs.

[0088] In one embodiment, the fabrication of the above stack structure 100 is, for example, to sequentially form AlGaAs / n-SiGe (N-type direct bandgap semiconductor) / AlGaAs / p-GaAs (P-type direct bandgap semiconductor) / AlGaAs on a silicon substrate (not shown), and then perform a wet oxidation process to oxidize only AlGaAs into Al2O3 as the tunneling layer. However, the present invention is not limited to this, and the single-photon emitting element 10 can also be fabricated using existing technologies.

[0089] Figure 2 is Figure 1 the energy band diagram of the single-photon emitting element, and the corresponding structure and film layers are also shown. In Figure 2Among them, SET represents the position of the single-electron quantum dot 106, SHT represents the position of the single-hole quantum dot 112, and the first and second tunneling layers 108, 114 are generally oxides and thus have a high potential barrier. When an electric field is supplied by an external drive circuit, the energy band in the high potential barrier region will be tilted, driving the tunneling of single electrons or single holes.

[0090] Figure 3 Then it is Figure 1 The equivalent circuit diagram of the single-photon emitting element. In Figure 3 C_spacer refers to the capacitance generated by the tunneling layer between SET and SHT, Cs_SET refers to the capacitance generated by the tunneling layer between SET and the source, Cd_SHT refers to the capacitance generated by the tunneling layer between SHT and the drain, Cg_SET refers to the capacitance generated by the tunneling layer between SET and the single-electron gate structure, Cg_SHT refers to the capacitance generated by the tunneling layer between SHT and the single-hole gate structure, Vs is the source voltage, Vd is the drain voltage, Vg_SET refers to the single-electron gate voltage, and Vg_SHT refers to the single-hole gate voltage.

[0091] Figure 4A It is an exploded view of a single-photon emitting element of another example of the first embodiment, in which some components are omitted to highlight the difference from Figure 1 the difference.

[0092] Please refer to Figure 4A In the single-photon emitting element 10', the number of single-electron quantum dots 106 is multiple (such as n), the number of single-hole quantum dots 112 is single, and the single-electron quantum dots 106 and the single single-hole quantum dot 112 are stacked on top of each other. The single-electron quantum dots 106 and the single-hole quantum dot 112 are also completely coated with the first and second tunneling layers 108 and 114, and the other components not shown are the same as those in Figure 1 completely the same.

[0093] Figure 4B It is Figure 4A The equivalent circuit diagram of the single-photon emitting element, where SET1, SET2... SETn respectively represent the first, second... nth single-electron quantum dots, and multiple controllable single-exciton arrays can be realized from this embodiment.

[0094] In another embodiment, the number of single-electron quantum dots 106 can be single, the number of single-hole quantum dots 112 can be multiple, and the single single-electron quantum dot 106 and the single-hole quantum dots 112 can be stacked on top of each other.

[0095] Figure 4C It is an exploded view of a single-photon emitting element of another example of the first embodiment, in which some components are omitted to highlight the difference from Figure 1 the difference.

[0096] Please refer to Figure 4C , in the single-photon emitting element 10", the number of single-electron quantum dots 106 is multiple, and the number of single-hole quantum dots 112 is also multiple, and they are horizontally adjacent to each other, forming another geometric arrangement of multiple controllable single-exciton arrays.

[0097] Figure 4D is an exploded view of a single-photon emitting element which is another example of the first embodiment, in which some components are omitted to highlight the difference from Figure 1 .

[0098] Please refer to Figure 4D , in the single-photon emitting element 10''', the number of single-electron quantum dots 106 and single-hole quantum dots 112 is multiple, and they are arranged in pairs vertically, forming yet another geometric arrangement of multiple controllable single-exciton arrays.

[0099] Figure 5 is an exploded view of a single-photon emitting element according to the second embodiment of the present invention, in which the same or similar components are denoted by the same component symbols as those in the first embodiment, and the content of the same or similar components can also be referred to the content of the first embodiment and will not be repeated here.

[0100] Please refer to Figure 5 , the difference between this embodiment and the first embodiment is that: the stacked structure 500 of the single-photon emitting element 50 further has an undoped direct-bandgap semiconductor layer 502, where the undoped direct-bandgap semiconductor layer 502 is a quantum dot layer or a quantum well layer. The undoped direct-bandgap semiconductor layer 502 is located between the single-electron quantum dot 106 and the single-hole quantum dot 112, and is isolated from the single-electron quantum dot 106 and the single-hole quantum dot 112 respectively through the first and second tunneling layers 108 and 114. The driving signal output by the external driving circuit 104 can control the tunneling injection of the single electron of the single-electron quantum dot 106 and the single hole of the single-hole quantum dot 112 into the undoped direct-bandgap semiconductor layer 502, so that electrons and holes recombine in the undoped direct-bandgap semiconductor layer 502 to emit a single photon. The material of the undoped direct-bandgap semiconductor layer 502 can be the same as or different from that of the single-electron quantum dot 106, and the material of the undoped direct-bandgap semiconductor layer 502 can also be the same as or different from that of the single-hole quantum dot 112.

[0101] Figure 6 is Figure 5 the equivalent circuit diagram of the single-photon emitting element, which is the same as Figure 3The difference lies in that there is an i representing an undoped direct-gap semiconductor layer between the SET and the SHT, where C_SET_spacer refers to the capacitance generated by the tunneling layer between the SET and the undoped direct-gap semiconductor layer, and C_SHT_spacer refers to the capacitance generated by the tunneling layer between the SHT and the undoped direct-gap semiconductor layer.

[0102] Figure 7 is an exploded view of another example of a single-photon emitting element of the second embodiment, where the same or similar components are denoted by the same component symbols as Figure 5 and the content of the same or similar components can also be referred to Figure 5 the content of, and will not be elaborated herein.

[0103] Please refer to Figure 7 , the single-photon emitting element 50' may further include a control gate structure 504 and an insulating layer 506. The control gate structure 504 completely surrounds the undoped direct-gap semiconductor layer 502, and the insulating layer 506 is located between the control gate structure 504 and the undoped direct-gap semiconductor layer 502. The control gate structure 504 can improve the control freedom.

[0104] Figure 8 is an exploded view of a single-photon emitting element according to the third embodiment of the present invention, where the same or similar components are denoted by the same component symbols as in the first embodiment, and the content of the same or similar components can also be referred to the content of the first embodiment, and will not be elaborated herein.

[0105] Please refer to Figure 8 , the difference between this embodiment and the first embodiment is that: the stacked structure 800 of the single-photon emitting element 80 includes: a quantum dot 802, a tunneling layer 804, a control gate structure 806, and an anti-state doped region carrier pool 808. The tunneling layer 804 completely coats the quantum dot 802, and the control gate structure 806 completely surrounds the quantum dot 802 and is isolated from the quantum dot 802 through the tunneling layer 804.

[0106] The anti-state doped region carrier pool 808 is adjacent to the quantum dot 802 and has a conductive state opposite to that of the quantum dot 802, and is isolated from the quantum dot 802 through the tunneling layer 804. The anti-state doped region carrier pool 808 is, for example, a one-dimensional or two-dimensional or three-dimensional semiconductor structure. The above-mentioned one-dimensional semiconductor structure includes a nanowire (Nano Wire), the above-mentioned two-dimensional semiconductor structure includes a quantum well (Quantum Well), and the above-mentioned three-dimensional semiconductor structure includes a bulk (Bulk).

[0107] Please continue to refer to Figure 8, in this embodiment, a single-electron quantum dot is taken as an example, where the single-electron quantum dot is an N-type direct bandgap semiconductor quantum dot or a metal quantum dot, and the inverted carrier pool 808 is a P-type carrier pool. The driving signal output by the external driving circuit 104 can control the single-electron tunneling injection of the quantum dot 802 into the inverted carrier pool 808 via the source electrode 102a, the drain electrode 102b, and the control gate structure 806, so that electron-hole pairs recombine in the inverted (P-type) carrier pool 808 to emit single photons.

[0108] In another embodiment, if the quantum dot 802 is a single-hole quantum dot, the inverted carrier pool is an N-type carrier pool, and the positions of the source electrode and the drain electrode are also interchanged. The single-hole quantum dot can be a P-type direct bandgap semiconductor quantum dot. Once the external driving circuit 104 outputs a driving signal, it can control the single-hole tunneling injection of the quantum dot 802 into the N-type carrier pool (inverted carrier pool 808) via the source electrode (the part pointed to by 102a), the drain electrode (the part pointed to by 102b), and the control gate structure 806, so that electron-hole pairs recombine in the N-type carrier pool to emit single photons.

[0109] Figure 9 is an exploded schematic view of a light-emitting device according to the fourth embodiment of the present invention.

[0110] Please refer to Figure 9 , the light-emitting device 90 of the fourth embodiment includes a structure 900 having an optical resonance cavity and a single-photon light-emitting element SPED, and the single-photon light-emitting element SPED is disposed in the structure 900 having an optical resonance cavity. The single-photon light-emitting element SPED can adopt any one of the elements proposed in the first to third embodiments.

[0111] For a single-photon emitting device (SPED), its main emission form is spontaneous emission. To significantly improve its efficiency, it is necessary to suppress the redundant and unutilized spontaneous emission and enhance the required spontaneous emission. The reason for spontaneous emission is that electrons return from the excited state to the ground state and emit photons after coupling with unoccupied optical modes in the form of photons. The probability of returning from the excited state to the ground state is related to the photonic density of state, electric field strength, and position. Therefore, the present invention controls spontaneous emission through the characteristics of the photonic crystal photonic bandgap. A point defect can be created in the photonic crystal, and a resonance cavity of the wavelength level is formed at the defect position due to the effect of the photonic bandgap. The confinement of light energy in the horizontal direction in the photonic crystal resonance cavity is due to the photonic bandgap, and in the vertical direction, the condition of total reflection is utilized. The loss of light energy is mainly contributed by the vertical direction. Since the photonic crystal resonance cavity has the characteristics of a high Q-factor and a very small mode volume (small Vm), the light-emitting device 90 of the fourth embodiment is expected to have an extremely high Q / Vm value. When Q / Vm is large enough, the interaction between electrons and light (quantum electro-dynamics) can be observed. Designing a photonic crystal resonance cavity with a high Q-factor and a very small mode volume can achieve suppressing the redundant and unutilized spontaneous emission and enhancing the required spontaneous emission. Because increasing the Q-factor of a certain frequency is to increase the number of photon modes at that frequency; while decreasing Vm is to enhance the electric field strength.

[0112] Therefore, in Figure 9 , the structure 900 with an optical resonance cavity is a photonic crystal structure. However, the present invention is not limited thereto. The types of semiconductor microresonators also include micropillar structures and microdisk structures. The common feature of these semiconductor microresonators is that they can form a very small mode volume, approximately V0 to (λ / n) 3 (where n is the refractive index of the semiconductor), and the quality factor Q can be as high as Q > 10 4 . The mode volumes of semiconductor microresonators are all much smaller than V0 << 1 μm 3 , and the transition dipole moment of the semiconductor is usually larger than that of an atom. Therefore, it is sufficient to meet the conditions for strong coupling between the SPED and the resonance cavity.

[0113] In addition, the light-emitting device 90 may further include a Bragg reflector (DBR) external cavity (not shown), which surrounds the structure 900 having an optical resonance cavity for condensing light. The DBR external cavity is, for example, an elliptical reflection cavity, but this component may be omitted in the present invention. When the energy and polarization of the emitted single photon match the optical resonance cavity, the emission efficiency of the single-photon light-emitting element SPED can be significantly improved.

[0114] In summary, the present invention uses a single-hole transistor (SHT) as the hole source and a single-electron transistor (SET) as the electron source, and injects single-electron tunneling into the direct-gap single-hole transistor directly, or vice versa, injects single-hole tunneling into the direct-gap single-electron transistor, so that electrons and holes recombine to emit a single photon, and the recombination center is in either the SET or the SHT. Another mode of the present invention is that the SET and the SHT respectively inject electrons and holes into the recombination region of an undoped direct-gap semiconductor layer, and this region may have an additional control gate to adjust the potential, and photons are emitted by recombination in this region. Another mode of the present invention is to use only one of the SET or the SHT as the recombination region, and cooperate with an inversion carrier pool to tunnel-inject inversion carriers into the recombination region, so that electrons and holes recombine to emit a single photon. The above modes can all be controlled by an external drive circuit through the control gate to control the switching speed. Therefore, the single-photon light-emitting element of the present invention can be regarded as a single-exciton transistor, and because the quantum dots in the SET and the SHT are externally coated with a tunneling (insulating) layer, there is also a chance to operate at room temperature. In addition, if the single-photon light-emitting element of the present invention is disposed in a structure having an optical resonance cavity, the emission efficiency of the quantum dots can be significantly improved.

[0115] Although the present invention is disclosed in combination with the above embodiments, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A single-photon emitting element, comprising: A stacked structure; A source electrode and a drain electrode, respectively disposed on opposite sides of the stacked structure; And An external drive circuit configured to output a drive signal, wherein The stacked structure includes: A single-electron quantum dot; A first tunneling layer that completely coats the single-electron quantum dot; A single-electron gate structure that completely surrounds the single-electron quantum dot and is isolated from the single-electron quantum dot through the first tunneling layer; A single-hole quantum dot adjacent to the single-electron quantum dot; A second tunneling layer that completely coats the single-hole quantum dot; and A single-hole gate structure that completely surrounds the single-hole quantum dot and is isolated from the single-hole quantum dot through the second tunneling layer, and According to the drive signal, controlling the single-electron tunneling of the single-electron quantum dot to inject into the single-hole quantum dot, so that electron-hole recombination occurs in the single-hole quantum dot to emit a single photon; or controlling the single-hole tunneling of the single-hole quantum dot to inject into the single-electron quantum dot, so that electron-hole recombination occurs in the single-electron quantum dot to emit a single photon.

2. The single-photon emitting element according to claim 1, wherein the single-electron quantum dot is an N-type direct-gap semiconductor quantum dot or a metal quantum dot.

3. The single-photon emitting element according to claim 1, wherein the single-hole quantum dot is a P-type direct-gap semiconductor quantum dot.

4. The single-photon emitting element according to claim 1, wherein the single-electron quantum dot and the single-hole quantum dot are of the same material or different materials.

5. The single-photon emitting element according to claim 1, wherein the number of the single-electron quantum dots is multiple, the number of the single-hole quantum dots is one, and the multiple single-electron quantum dots and the single single-hole quantum dot are stacked on top of each other.

6. The single-photon emitting element according to claim 1, wherein the number of the single-electron quantum dots is one, the number of the single-hole quantum dots is multiple, and the single single-electron quantum dot and the multiple single-hole quantum dots are stacked on top of each other.

7. The single-photon emitting element according to claim 1, wherein the number of the single-electron quantum dots is multiple, the number of the single-hole quantum dots is multiple, and the multiple single-electron quantum dots and the multiple single-hole quantum dots are arranged in pairs vertically.

8. A single-photon emitting element, comprising: A stacked structure; A source electrode and a drain electrode, respectively disposed on opposite sides of the stacked structure; And An external drive circuit configured to output a drive signal, wherein The stacked structure includes: A single-electron quantum dot; A first tunneling layer that completely coats the single-electron quantum dot; A single-electron gate structure that completely surrounds the single-electron quantum dot and is isolated from the single-electron quantum dot through the first tunneling layer; A single-hole quantum dot; A second tunneling layer that completely coats the single-hole quantum dot; A single-hole gate structure that completely surrounds the single-hole quantum dot and is isolated from the single-hole quantum dot through the second tunneling layer; and An undoped direct-bandgap semiconductor layer, which is between the single-electron quantum dot and the single-hole quantum dot, and is isolated from the single-electron quantum dot and the single-hole quantum dot respectively through the first tunneling layer and the second tunneling layer, and controls the tunneling injection of the single electron of the single-electron quantum dot and the single hole of the single-hole quantum dot into the undoped direct-bandgap semiconductor layer according to the driving signal, so that electrons and holes recombine in the undoped direct-bandgap semiconductor layer to emit single photons.

9. The single-photon emitting element according to claim 8, wherein the single-electron quantum dot is an N-type direct-bandgap semiconductor quantum dot or a metal quantum dot.

10. The single-photon emitting element according to claim 8, wherein the single-hole quantum dot is a P-type direct-bandgap semiconductor quantum dot.

11. The single-photon emitting element according to claim 8, wherein the single-electron quantum dot and the single-hole quantum dot are of the same material or different materials.

12. The single-photon emitting element according to claim 8, further comprising: a control gate structure that completely surrounds the undoped direct-bandgap semiconductor layer; and an insulating layer located between the control gate structure and the undoped direct-bandgap semiconductor layer.

13. The single-photon emitting element according to claim 8, wherein the undoped direct-bandgap semiconductor layer is a quantum dot layer or a quantum well layer.

14. A single-photon emitting element, comprising: a stacked structure; a source electrode and a drain electrode respectively disposed on opposite sides of the stacked structure; and an external drive circuit configured to output a driving signal, wherein the stacked structure comprises: a quantum dot, which is either a single-electron quantum dot or a single-hole quantum dot; a tunneling layer that completely coats the quantum dot; a control gate structure that completely surrounds the quantum dot and is isolated from the quantum dot through the tunneling layer; and a counter-carrier pool, which is adjacent to the quantum dot and has a conductivity state opposite to that of the quantum dot, and is isolated from the quantum dot through the tunneling layer, and controls the tunneling injection of the single electron or single hole of the quantum dot into the counter-carrier pool according to the driving signal, so that electrons and holes recombine in the counter-carrier pool to emit single photons.

15. The single-photon emitting element according to claim 14, wherein the single-electron quantum dot is an N-type direct-bandgap semiconductor quantum dot or a metal quantum dot.

16. The single-photon emitting element according to claim 14, wherein the single-hole quantum dot is a P-type direct-bandgap semiconductor quantum dot.

17. The single-photon emitting element according to claim 14, wherein the quantum dot is the single-electron quantum dot and the counter-carrier pool is a P-type carrier pool.

18. The single-photon emitting element according to claim 14, wherein the quantum dot is the single-hole quantum dot and the counter-carrier pool is an N-type carrier pool.

19. The single-photon emitting element according to claim 14, wherein the counter-carrier pool is a one-dimensional or two-dimensional or three-dimensional semiconductor structure.

20. The single-photon light-emitting element according to claim 19, wherein the one-dimensional semiconductor structure comprises a nanowire, the two-dimensional semiconductor structure comprises a quantum well, and the three-dimensional semiconductor structure comprises a bulk.

21. A light-emitting device, comprising: A structure having an optical resonance cavity; And The single-photon light-emitting element according to any one of claims 1 to 20, disposed within the structure having an optical resonance cavity.

22. The light-emitting device according to claim 21, wherein the structure having an optical resonance cavity comprises a microcylindrical structure, a photonic crystal structure, or a microdisk structure.

23. The light-emitting device according to claim 21, further comprising an external cavity of a Bragg reflector (DBR) surrounding the structure having an optical resonance cavity.

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