CN107895681A - A kind of photocathode and preparation method thereof - Google Patents
A kind of photocathode and preparation method thereof Download PDFInfo
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- 238000002360 preparation method Methods 0.000 title claims description 13
- 239000004065 semiconductor Substances 0.000 claims abstract description 46
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- 230000015572 biosynthetic process Effects 0.000 claims abstract description 6
- 239000010410 layer Substances 0.000 claims description 129
- 239000010406 cathode material Substances 0.000 claims description 25
- 230000004913 activation Effects 0.000 claims description 23
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- 239000002344 surface layer Substances 0.000 claims description 12
- 239000002178 crystalline material Substances 0.000 claims description 4
- 230000003213 activating effect Effects 0.000 claims description 3
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- 229910052594 sapphire Inorganic materials 0.000 description 19
- 239000010980 sapphire Substances 0.000 description 19
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- 229910001218 Gallium arsenide Inorganic materials 0.000 description 11
- 238000010586 diagram Methods 0.000 description 11
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- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 6
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- 238000005286 illumination Methods 0.000 description 6
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- 229910000673 Indium arsenide Inorganic materials 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/34—Photo-emissive cathodes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/12—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes
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Abstract
The invention discloses a kind of photocathode, including substrate, the p-type AlN cushions formed on substrate, the p-type Al formed on p-type AlN cushionsxGa1‑xN emission layers and formation are in p-type AlxGa1‑ xLow-gap semiconductor superficial layer on N emission layers；Wherein, the material of the low-gap semiconductor superficial layer is the semi-conducting material of energy gap≤2.3eV at room temperature, the p-type AlxGa1‑xX scope is 0≤x ＜ 1 in N emission layers.The photocathode of the present invention is in p-type AlxGa1‑xLow-gap semiconductor superficial layer, low-gap semiconductor superficial layer atom and p-type Al are grown on N emission layersxGa1‑xN emission layer atoms are combined in the form of covalent bond, are advantageous to improve AlxGa1‑xN material surface band structures, photocathode surface work function is reduced, improve the probability on electron tunneling photocathode surface.
Description
Technical field
The present invention relates to photocathode electron source technical field.More particularly, to a kind of photocathode and its preparation side
Method.
Background technology
Photocathode is the core component of opto-electronic conversion in micro light detecting device, and photocathode performance in recent years
Performance improves year by year, while the photoelectric cathode materials species of different-waveband also gradually increases.Traditional photovoltaic negative electrode has quantum effect
The advantages that rate height, fast response time, dark current be small and emitted electron energy is concentrated, reflective and Transmission-mode GaAs photocathode light
The peak electron emissivities of spectrum response respectively reach 379.9 and 245.2mA/W.
Traditional photovoltaic negative electrode mainly reduces the work function of itself by the way of caesium (Cs) atomic adsorption, and GaAs photoelectricity is cloudy
Pole can form negative electron affinity (NEA) surface, from valence to conduction band in electronics have larger probability through surface potential barrier escape
Into vacuum, therefore there is higher electron emissivity.But the adsorption thickness of Cs atoms is only single atomic layer, Cs atoms
Easily it is desorbed in high temperature or larger emission from cathode surface, causes cathode performance to reduce.The electricity of photocathode simultaneously
Sub- emission level requires more strict, CO to the gas atmosphere of vacuum chamber2, CO and H2O etc. can suppress the electron emission energy of negative electrode
Power, and the electron emissivity of negative electrode can not recover again, so traditional photocathode can not be applied to large-current electric
The device and instrument of component.
Therefore, photocathode is applicable only in the relatively low environment of intensity of illumination, and under conditions of intensity of illumination is higher,
The electron emissivity of negative electrode can drastically reduce, or even lose electron emissivity, and result in photocathode can not be used as electronics
Source is applied in the device and instrument of other high currents.So photocathode is only applied to gleam image intensifier part and part at present
In free electron laser, do not apply in other need the vacuum device and instrument of electron source.
In order to solve the problems, such as that Traditional photovoltaic negative electrode is not used to high light conditions, the U.S. in 2010 proposes one kind and exempts to swash
GaN photocathodes living, photoelectronic transport efficiency in emission of cathode layer is improved by adjusting foreign atom with doping concentration
And surface work function, emission of cathode layer include p-type GaN emission layers, Si delta doping layers GaN layer and n-type GaN superficial layers, surface thickness
The electron emission capability of the bigger negative electrode of degree is lower, and when photon energy is 5eV, the quantum efficiency of negative electrode reaches 0.1%.Electric section of China
55th research institute proposes a kind of p-i-n structure and exempts to activate GaN photocathodes, is equally to utilize doping concentration adjustment emission of cathode
The band structure of layer and the GaN superficial layers of n-type, to realize the electron emission of negative electrode.It is this without Cs activation photocathode with
Traditional photovoltaic negative electrode is compared to can possess higher life-span and stability, but GaN crystal is wide bandgap semiconductor, the conductance of material
Rate is smaller, and conductive capability is poor, and for a large amount of electronics after cathode surface transmitting, cathode plane is in electropositive, the electronics on cathode electrode
It can not in time add in emission of cathode layer, turn into an important factor for limiting cathode performance.
Therefore, although exempt from activate photocathode be adapted to intense light irradiation, especially using high power laser as light source when,
The emission current of photocathode is but far above Traditional photovoltaic negative electrode, while has the emitting performance stablized and longer use longevity
Life, it is a kind of simple packaging technology, modulation and desired electrical component easy to use, but exempts to activate the quantum efficiency of photocathode
Far below traditional photocathode.
Accordingly, it is desirable to provide one kind can either be applied to high light conditions, and can enough improves photocathode quantum efficiency
The high current density photocathode of strong photoresponse.
The content of the invention
It is an object of the present invention to provide a kind of photocathode.
It is another object of the present invention to provide a kind of preparation method of photocathode.
To reach above-mentioned purpose, the present invention uses following technical proposals：
A kind of photocathode, the photocathode include substrate, the p-type AlN cushions formed on substrate, formed in p
P-type Al on type AlN cushionsxGa1-xN emission layers and formation are in p-type AlxGa1-xLow-gap semiconductor surface on N emission layers
Layer；Wherein, the material of the low-gap semiconductor superficial layer is the semi-conducting material of energy gap≤2.3eV at room temperature, the p
Type AlxGa1-xX scope is 0≤x ＜ 1 in N emission layers.Compared with Traditional photovoltaic negative electrode Cs-O adsorbs activation technology, the present invention
In p-type AlxGa1-xLow-gap semiconductor superficial layer is grown on N emission layers, low-gap semiconductor superficial layer atom becomes component with p-type
Varying doping AlxGa1-xN emission layer atoms are combined in the form of covalent bond, are advantageous to improve AlxGa1-xN material surface band structures, drop
Low photocathode surface work function, improves the probability on electron tunneling photocathode surface, and the photocathode of acquisition has stability
High, anti-Ions Bombardment ability is strong and the advantages that emission is big.Do not have still in terms of photocathode and its technology of preparing at present
Have and content identical document report described in this patent.
Preferably, the material of the low-gap semiconductor superficial layer can be n-type, intrinsic or p-type iii-v crystal material
Material；Further, the iii-v crystal in the n-type, intrinsic or p-type iii-v crystalline material can be AlAs, GaAs,
The crystal such as GaP, InAs, InP or iii-v multi-element compounds.Preferred surface layer material in the present invention can more effectively change
Cathode material surface energy band structure, cathode surface potential barrier is reduced, improve cathode electronics emissivities.
Preferably, the material of the low-gap semiconductor superficial layer can be p-type Group III-V crystalline material, and foreign atom is
Zn or Be etc., doping concentration≤1 × 1020cm-3.The narrow taboo of p-type can be more effectively improved in doping concentration scope of the present invention
Electrical conductivity with semiconductor surface layer.
Preferably, the material of the low-gap semiconductor superficial layer can be n-type Group III-V crystalline material, and foreign atom is
Si, Sn, Ge, C, Te or S etc., doping concentration≤1 × 1020cm-3.Can be more effectively in doping concentration scope of the present invention
Improve the electrical conductivity of p-type low-gap semiconductor superficial layer.
Preferably, the scope of the thickness h of the low-gap semiconductor superficial layer is 0<h≤200nm.As long as deposited in the present invention
In low-gap semiconductor superficial layer, heterojunction structure can be reduced when wherein low-gap semiconductor surface layer thickness is more than 200nm
To the humidification of electron transport, the improvement to cathode surface potential barrier is reduced.In some embodiments of the present invention, institute
Stating low-gap semiconductor surface layer thickness can be, such as：0.5~100nm, 0.5~50nm, 0.5~10nm, 10~200nm, 10
~100nm, 10~50nm, 50~200nm, 50~100nm etc., more preferably 0.5~10nm, the effect that preferred scheme obtains
Fruit is optimal.
Preferably, the foreign atom of the p-type AlN cushions can be Mg, and doping way can be Uniform Doped, doping concentration
≤1×1019cm-3.Be advantageous to improve the ability of cushion orientation supplement electronics in the range of the Mg doping concentrations of the present invention, mix
Miscellaneous concentration is more than 1 × 1019cm-3The efficiency of ionization of foreign atom can be reduced, influences the growth quality of crystal.
Preferably, the p-type AlN buffer layer thicknesses can be 10~1000nm.Heretofore described buffer layer thickness is less than
10nm can reduce emission layer crystal growth quality, can then cause incident light to be decayed in AlN cushions more than 1000nm.In this hair
In bright some embodiments, the p-type AlN buffer layer thicknesses can be, such as：10~700nm, 10~600nm, 10~
500nm, 10~400nm, 10~300nm, 10~200nm, 10~100nm, 10~50nm, 10~30nm, 30~1000nm, 30
~700nm, 30~600nm, 30~500nm, 30~400nm, 30~300nm, 30~200nm, 30~100nm, 30~50nm,
50~1000nm, 50~700nm, 50~600nm, 50~500nm, 50~400nm, 50~300nm, 50~200nm, 50~
100nm, 100~1000nm, 100~700nm, 100~600nm, 100~500nm, 100~400nm, 100~300nm, 100
~200nm, 200~1000nm, 200~700nm, 200~600nm, 200~500nm, 200~400nm, 200~300nm,
300~1000nm, 300~700nm, 300~600nm, 300~500nm, 300~400nm, 400~1000nm, 400~
700nm, 400~600nm, 400~500nm, 500~1000nm, 500~700nm, 500~600nm, 600~1000nm, 600
~700nm, 700~1000nm etc., more preferably 50~700nm, the best results that preferred scheme obtains.
Preferably, the p-type AlxGa1-xThe foreign atom of N emission layers is Mg, and doping way is grade doping, and concentration is terraced
The number of degrees are m, and m >=1, doping concentration are followed successively by N from low-gap semiconductor superficial layer toward p-type AlN cushions direction1、N2、…、
Nm-1、Nm, and meet 1 × 1015cm-3≤N1≤N2≤…≤Nm-1≤Nm≤1×1020cm-3.Emission layer of the present invention can be uniformly to mix
Miscellaneous, or varying doping, doping concentration scope can improve electronics on the basis of the growth quality of crystal and electric conductivity is ensured
To the transport efficiency of cathode surface.
Preferably, the p-type AlxGa1-xN emission layers include n p-type AlxGa1-xN sublayers, wherein n >=1, from low energy gap half
Surface conductor layer is toward each layer of direction of p-type AlN cushions p-type AlxGa1-xThe Al components of N sublayers are followed successively by x1、x2、…、xn-1、
xn, and meet 0≤x1≤x2≤…≤xn-1≤xn＜ 1.P-type Al in the present inventionxGa1-xThe Al components of N emission layers are past from superficial layer
Cushion direction gradually increases, so as to which the band structure change formed is beneficial to improve photocathode internal electron to photoelectricity the moon
The transport efficiency of pole surface direction.
Preferably, the p-type AlxGa1-xN emission layers thickness can be 10~300nm.Heretofore described emission layer thickness
Less than the absorption efficiency that 10nm can reduce incident light, transporting for electronics can be influenceed more than 300nm.In some specific real of the present invention
Apply in mode, the p-type AlxGa1-xN emission layers thickness can be, such as：10~200nm, 10~170nm, 10~150nm, 10
~130nm, 10~100nm, 10~80nm, 10~45nm, 45~300nm, 45~200nm, 45~170nm, 45~150nm,
45~130nm, 45~100nm, 45~80nm, 80~300nm, 80~200nm, 80~170nm, 80~150nm, 80~
130nm, 80~100nm, 100~300nm, 100~200nm, 100~170nm, 100~150nm, 100~130nm, 130~
300nm, 130~200nm, 130~170nm, 130~150nm, 150~300nm, 150~200nm, 150~170nm, 170~
300nm, 170~200nm, 200~300nm etc., more preferably 45~80nm, the best results that preferred scheme obtains.
Preferably, the substrate can be Sapphire Substrate.The thickness of substrate is not particularly limited and can be with the present invention
Suitably selected according to purpose.
In addition, substrate of the present invention, p-type AlN cushions, p-type AlxGa1-xN emission layers and low-gap semiconductor surface
The shape of layer is not particularly limited and can suitably selected according to expected purpose.
The preparation method of above-mentioned photocathode, comprises the following steps：
P-type AlN cushions are formed on substrate, p-type Al is formed on p-type AlN cushionsxGa1-xN emission layers, in p-type
AlxGa1-xLow-gap semiconductor superficial layer is formed on N emission layers, obtains photoelectric cathode materials；Photoelectric cathode materials are swashed
It is living, obtain photocathode.
Preferably, the generation type of the p-type AlN cushions can be MOCVD (Metal-organic Chemical
Vapor Deposition metallo-organic compounds chemical gaseous phase deposition) or MBE (Molecular Beam Epitaxy molecular beams
Extension) epitaxial growth regime.
Preferably, the p-type AlxGa1-xThe generation type of N emission layers can be MOCVD or MBE epitaxial growth regimes.
Preferably, the generation type of the low-gap semiconductor superficial layer can be MOCVD, MBE, VPE (Vapor Phase
Epitaxy vapour phase epitaxies), LEP (Liqiud Phase Epitaxy liquid phase epitaxies) or thermal evaporation homepitaxy growth technique.
Preferably, the active mode of the photoelectric cathode materials activates for annealing.The present invention need not carry out Cs-O absorption and swash
Living, annealing activation can obtain photocathode.Annealing activation in the present invention is conventional technical means, be will not be repeated here.
Preferably, the preparation method of the photocathode specifically comprises the following steps：
1) in the Sapphire Substrate of twin polishing, p-type AlN bufferings are grown using MOCVD or MBE epitaxial growth regimes
Layer；
2) MOCVD or MBE epitaxial growth regimes, and the p-type doping process of semi-conducting material are used, is buffered in p-type AlN
P-type Al is grown on layerxGa1-xN emission layers；
3) MOCVD, MBE, VPE, LEP or thermal evaporation homepitaxy growth technique are used, in p-type AlxGa1-xIt is raw on N emission layers
Long low-gap semiconductor superficial layer, obtains photoelectric cathode materials；
4) photoelectric cathode materials are put into vacuum system to be heat-treated, remove the foreign atom of cathode surface；
5) annealing activation is carried out to photoelectric cathode materials, obtains photocathode.
How to make photocathode to be applied to high light conditions and there is strong emission current ability, the present invention overcomes
Technical problem underlying.Traditional photovoltaic negative electrode enters line activating using Cs-O suction types, although its quantum efficiency is higher, Cs is former
Son can be relatively low in the combination of cathode surface, and stability is poor, so the photocathode of Cs-O activation is not suitable for being operated in intense light conditions,
It cannot act as high current density electron source.
In order to overcome above-mentioned technical problem, the present invention is in the ultra-thin low-gap semiconductor superficial layer of cathode material superficial growth
To substitute traditional Cs-O Activiation methods, not only strengthen cathode surface near zone built in field intensity, strengthen transporting for electronics
Performance, and the vacuum level of AlGaN planes of crystal is significantly reduced, so as to make photocathode have high current density electric
The ability of son transmitting.Ultra-thin low-gap semiconductor superficial layer is combined in a manner of covalent bond with AlGaN crystal phases in addition, compares Cs
Atom is more stable in the absorption of AlGaN planes of crystal, so that the negative electrode of the present invention, which has, bears high current density electron emission
Ability.For REINFORCED AlxGa1-xTo the transport capability in cathode surface direction, emission layer is become using change component to be mixed electronics in N emission layers
Miscellaneous structure design, built in field direction is internally formed by being internally pointed to cathode surface in emission layer, electronics is expanded to cathode surface
Load in bulk and produce drift motion on the basis of moving, improve the diffusion length of electronics, the final electron emissivity for strengthening negative electrode.I.e. originally
The technical scheme of invention is a unified entirety, and each technical characteristic is not Line independent, between different technologies feature
It can interact, therefore the realization of the final technique effect of the present invention, it is necessary to one dependent on all technical characteristic organic integration
The entirety that can not be split, rather than some technical characteristics simple plus and.
In addition, unless otherwise specified, any scope described in the present invention includes any number between end value and end value
Any subrange that any number between value and end value or end value is formed.
Beneficial effects of the present invention are as follows：
(1) present invention substitutes the activation side of Traditional photovoltaic negative electrode Cs-O atomic adsorptions using ultra-thin low-gap semiconductor layer
Formula, the photocathode of acquisition have the advantages that stability is high, anti-Ions Bombardment ability is strong and emission is big.
(2) atom of photocathode surface low-gap semiconductor layer of the present invention and the atom of transmitting layer surface are formed covalently
Key, the combination energy of emission of cathode layer surface activated atom is greatly improved, the negative electrode for further increasing the present invention is born greatly
The ability of current density electron emission.
(3) the Al components of p-type AlGaN emission layers reduce Zi internal to surface to be gradual from high to low in the present invention, this
Structure can be such that band structure in emission layer is gradually reduced from inside to surface, significantly reduce the vacuum of AlGaN planes of crystal
Energy level, therefore electronics can be made and moved in emission layer with two kinds of motion modes of diffusion plus drift to cathode surface, add electronics
Diffusion length, be finally effectively improved the quantum efficiency of photocathode.
Brief description of the drawings
The embodiment of the present invention is described in further detail below in conjunction with the accompanying drawings.
Fig. 1 shows the structural representation of photocathode in the present invention：Fig. 1 (a) shows photocathode optics knot in the present invention
Structure and Al component schematic diagrames；Fig. 1 (b) shows photocathode optical texture and Al in the present inventionxGa1-xN emission layers concentration is illustrated
Figure；Wherein：1- Sapphire Substrates, 2-p type AlN cushions, 3-p types AlxGa1-xN emission layers, 4- low-gap semiconductor superficial layers.
Fig. 2 shows photocathode optical texture and Al component schematic diagrames in the embodiment of the present invention 1 and comparative example 1：Fig. 2 (a)
Photocathode optical texture and Al component schematic diagrames in comparative example 1 of the present invention is shown；Fig. 2 (b) is shown in the embodiment of the present invention 1
Photocathode optical texture and Al component schematic diagrames；Wherein：201- Sapphire Substrates, 202-p type AlN cushions, 203-p types
GaN emission layers, 204- Intrinsical GaAs superficial layers.
Fig. 3 shows photocathode optical texture and Al component schematic diagrames in the embodiment of the present invention 2, wherein：301- sapphires
Substrate, 302-p type AlN cushions, 303-p type GaN emission layers, 304- Intrinsical InP superficial layers.
Fig. 4 shows photocathode optical texture and Al component schematic diagrames in the embodiment of the present invention 3, wherein：401- sapphires
Substrate, 402-p type AlN cushions, 403-p types Al0.9Ga0.1N emission layers, 404-p types Al0.65Ga0.35N emission layers, 405-p types
GaN emission layers, 406-p types become component varying doping AlxGa1-xN emission layers, 407- Intrinsical GaAs superficial layers.
Fig. 5 shows the quantum efficiency curve of photocathode in the embodiment of the present invention 1,2 and 3.
Fig. 6 shows the quantum efficiency curve of photocathode in comparative example 2 of the present invention.
Embodiment
In order to illustrate more clearly of the present invention, the present invention is done further with reference to preferred embodiments and drawings
It is bright.Similar part is indicated with identical reference in accompanying drawing.It will be appreciated by those skilled in the art that institute is specific below
The content of description is illustrative and be not restrictive, and should not be limited the scope of the invention with this.
Fig. 1 shows the structural representation of photocathode in the present invention, and the photocathode includes Sapphire Substrate 1, formed
P-type AlN cushions 2, the p-type Al formed on p-type AlN cushions 2 in Sapphire Substrate 1xGa1-xN emission layers 3 and shape
Into in p-type AlxGa1-xLow-gap semiconductor superficial layer 4 on N emission layers 3.
In Fig. 1, the p-type AlN cushions are Uniform Doped, foreign atom Mg；
The p-type AlxGa1-xN emission layers, foreign atom Mg, doping way are grade doping, doping concentration gradient number
For m, and m >=1, Al from top to bottomxGa1-xN emission layer concentration is respectively N1、N2、…、Nm-1、Nm, and meet 1 × 1015cm-3≤N1
≤N2≤…≤Nm-1≤Nm≤1×1020cm-3, as shown in Fig. 1 (b)；
The p-type becomes component varying doping AlxGa1-xN emission layers can be by n p-type AlxGa1-xN sublayers are formed, wherein n >=1,
P-type Al from top to bottomxGa1-xThe Al components of N sublayers are respectively x1、x2、…、xn-1、xn, and meet 0≤x1≤x2≤…≤xn-1≤
xn＜ 1, as shown in Fig. 1 (a).
Embodiment 1
Shown in a kind of photocathode, its optical texture and Al component structures schematic diagram such as Fig. 2 (b), including Sapphire Substrate
201st, the p-type doping AlN cushions 202 formed in Sapphire Substrate 201, the p formed on p-type doping AlN cushions 202
The Intrinsical GaAs superficial layers 204 of type GaN emission layers 203 and formation on p-type GaN emission layers 203.
Its preparation method comprises the following steps：
1) grown using MOCVD epitaxy growth pattern in the Sapphire Substrate 201 for the twin polishing that thickness is 0.46mm
Thickness is 200nm p-type AlN cushions 202, and its foreign atom is Mg, and doping concentration is 1 × 1016cm-3；
2) MOCVD epitaxy growth pattern, and the p-type doping process of semi-conducting material are used, in p-type AlN cushions 202
Upper growth p-type AlxGa1-xN emission layers, wherein p-type AlxGa1-xSublayer number n=1, the Al component of N emission layers are 0, doping concentration ladder
Number of degrees m=1, i.e. AlxGa1-xN emission layers are now GaN emission layers 203, thickness 80nm, foreign atom Mg, doping concentration
For 1 × 1018cm-3；
3) photoelectric cathode materials that step 2) obtains are respectively put into acetone and ethanol and be cleaned by ultrasonic 5 minutes, with
Remove the organic matter that cathode material surface is stain in transportation.It is then placed in 800 DEG C of thermal cleanings 20 of progress in vacuum system
Minute, to remove cathode material surface C, O compounds, so as to obtain atomically clean surfaces.
4) using LEP growth patterns growth GaAs crystal, i.e., grown on the p-type GaN emission layers 203 that step 3) obtains thick
Degree is about 5nm Intrinsical GaAs superficial layers 204；
5) photoelectric cathode materials obtained to step 4) carry out annealing activation.
By above-mentioned steps, photocathode component is made.
The quantum efficiency of photocathode after test activation.Fig. 5 is the quantum efficiency curve of negative electrode, and horizontal coordinate is photon
Energy, vertical coordinate are the quantum efficiencies of photocathode.The quantum efficiency of negative electrode is only 10 as can be seen from Figure 5-3~10-2Amount
Level, it is 10 less than quantum efficiency-1The Cs/O activation photocathodes of magnitude, but be that (photon energy is 266nm in wavelength
4.66eV) power is that the lasting emission current of photocathode can reach 0.92mA, and stability is much larger than under 1W laser illumination
The photocathode of Cs/O activation.
Comparative example 1
Shown in a kind of photocathode, its optical texture and Al component structures schematic diagram such as Fig. 2 (a), including Sapphire Substrate
201st, the p-type AlN cushions 202 formed in Sapphire Substrate 201, the p-type GaN hairs formed on p-type AlN cushions 202
Penetrate layer 203.
Its preparation method the difference is that only with embodiment 1：Not comprising step 4), step 3) is obtained in step 5)
Photoelectric cathode materials carry out annealing activation.
By above-mentioned steps, photocathode component is made,
The quantum efficiency of photocathode after test activation, launches in test scope inner cathode no current, cathode quantum effect
Rate is 0.
Comparative example 2
Shown in a kind of photocathode, its optical texture and Al component structures schematic diagram such as Fig. 2 (a), including Sapphire Substrate
201st, the p-type AlN cushions 202 formed in Sapphire Substrate 201, the p-type GaN hairs formed on p-type AlN cushions 202
Penetrate layer 203.
Its preparation method the difference is that only with embodiment 1：Not comprising step 4), step 3) is obtained in step 5)
Photoelectric cathode materials annealed, then enter line activating using Cs/O active modes.
By above-mentioned steps, photocathode component is made.
The quantum efficiency of photocathode after test activation.Fig. 6 is the quantum efficiency curve of negative electrode, and horizontal coordinate is photon
Energy, vertical coordinate are the quantum efficiencies of photocathode.The quantum efficiency of photocathode reaches when photon energy is 5.167eV
23.7%.Although the quantum efficiency of Cs/O photocathodes reaches 10-1Magnitude, higher than low-gap semiconductor surface in embodiment 1
Photocathode, as shown in figure 5, but 266nm (photon energy 4.66eV) power be 1W laser illumination under, negative electrode it is steady
Qualitative excessively poor, the cathode current emission decays to rapidly 0, therefore is not suitable for the electron source as high current vacuum device.
Embodiment 2
A kind of photocathode, its optical texture and Al component structures schematic diagram as shown in figure 3, including Sapphire Substrate 301,
P-type AlN cushions 302, the p-type GaN emission layers formed on p-type AlN cushions 302 formed in Sapphire Substrate 301
The 303 Intrinsical InP superficial layers 304 with formation on p-type GaN emission layers 303.
Its preparation method comprises the following steps：
1) grown using MOCVD epitaxy growth pattern in the Sapphire Substrate 301 for the twin polishing that thickness is 0.46mm
Thickness is 200nm p-type AlN cushions 302, and its foreign atom is Mg, and doping concentration is 1 × 1016cm-3；
2) MOCVD epitaxy growth pattern, and the p-type doping process of semi-conducting material are used, in p-type AlN cushions 302
Upper growth p-type AlxGa1-xN emission layers, wherein p-type AlxGa1-xSublayer number n=1, the Al component of N emission layers are 0, doping concentration ladder
Number of degrees m=1, i.e. AlxGa1-xN emission layers are now GaN emission layers 303, thickness 80nm, foreign atom Mg, doping concentration
For 1 × 1018cm-3；
3) photoelectric cathode materials that step 2) obtains are respectively put into acetone and ethanol and be cleaned by ultrasonic 5 minutes, with
Remove the organic matter that cathode material surface is stain in transportation.It is then placed in 800 DEG C of thermal cleanings 20 of progress in vacuum system
Minute, to remove cathode material surface C, O compounds, so as to obtain atomically clean surfaces.
4) LEP growth pattern grown InP crystal, i.e., the sheet that growth thickness is about 5nm on p-type GaN emission layers 303 are used
Sign type InP superficial layers 304；
5) photoelectric cathode materials obtained to step 4) carry out annealing activation.
The quantum efficiency of photocathode after test activation.Fig. 5 is the quantum efficiency curve of negative electrode, and horizontal coordinate is photon
Energy, vertical coordinate are the quantum efficiencies of photocathode.The quantum efficiency of negative electrode is only 10 as can be seen from Figure 5-3~10-2Amount
Level, it is 10 less than quantum efficiency-1The Cs/O activation photocathodes of magnitude, but be that (photon energy is 266nm in wavelength
4.66eV) power is that the lasting emission current of photocathode can reach 1.5mA, and stability is much larger than under 1W laser illumination
The photocathode of Cs/O activation.
Embodiment 3
A kind of photocathode, its optical texture and Al component structures schematic diagram as shown in figure 3, including Sapphire Substrate 401,
P-type AlN cushions 402, the p-type Al formed on p-type AlN cushions 402 formed in Sapphire Substrate 4010.9Ga0.1N
Emission layer 403, formed in p-type Al0.9Ga0.1P-type Al on N emission layers 4030.65Ga0.35N emission layers 404, formed in p-type
Al0.65Ga0.35The Intrinsical GaAs tables of p-type GaN emission layers 405 and formation on p-type GaN emission layers 405 on N emission layers 404
Surface layer 407.
Its preparation method comprises the following steps：
1) grown using MOCVD epitaxy growth pattern in the Sapphire Substrate 401 for the twin polishing that thickness is 0.46mm
Thickness is 200nm p-type AlN cushions 402, and foreign atom Mg, doping concentration is 1 × 1016cm-3；
2) MOCVD epitaxy growth pattern, and the p-type doping process of semi-conducting material are used, in p-type AlN cushions 402
Upper growth p-type AlxGa1-xN emission layers, its doping concentration gradient number m=1, foreign atom Mg, doping concentration is 1 × 1018cm-3；
P-type AlxGa1-xThe sublayer number n=3 of N emission layers, the Al components of 3 sublayers are respectively 0.9,0.65 and 0, corresponding
Thickness be respectively 5nm, 5nm and 35nm, i.e. AlxGa1-xN emission layers include the p-type Al that thickness is 5nm0.9Ga0.1N emission layers
403rd, thickness is 5nm p-type Al0.65Ga0.35N emission layers 404 and the p-type GaN emission layers 405 that thickness is 35nm；
3) photoelectric cathode materials that step 2) obtains are respectively put into acetone and ethanol and be cleaned by ultrasonic 5 minutes, with
Remove the organic matter that cathode material surface is stain in transportation.It is then placed in 800 DEG C of thermal cleanings 20 of progress in vacuum system
Minute, to remove cathode material surface C, O compounds, so as to obtain atomically clean surfaces.
4) using LEP growth patterns growth GaAs crystal, i.e., growth thickness is about 5nm's on p-type GaN emission layers 405
Intrinsical GaAs superficial layers 406；
5) photoelectric cathode materials obtained to step 4) carry out annealing activation.
The quantum efficiency of photocathode after test activation.Fig. 5 is the quantum efficiency curve of negative electrode, and horizontal coordinate is photon
Energy, vertical coordinate are the quantum efficiencies of photocathode.The quantum efficiency of negative electrode is only 10 as can be seen from Figure 5-3~10-2Amount
Level, it is 10 less than quantum efficiency-1The Cs/O activation photocathodes of magnitude, but be that (photon energy is 266nm in wavelength
4.66eV) power is that the lasting emission current of photocathode can reach 2.3mA, and stability is much larger than under 1W laser illumination
The photocathode of Cs/O activation.
Obviously, the above embodiment of the present invention is only intended to clearly illustrate example of the present invention, and is not pair
The restriction of embodiments of the present invention, for those of ordinary skill in the field, may be used also on the basis of the above description
To make other changes in different forms, all embodiments can not be exhaustive here, it is every to belong to this hair
Row of the obvious changes or variations that bright technical scheme is extended out still in protection scope of the present invention.
Claims (10)
1. a kind of photocathode, it is characterised in that the photocathode includes substrate, the p-type AlN bufferings formed on substrate
Layer, the p-type Al formed on p-type AlN cushionsxGa1-xN emission layers and formation are in p-type AlxGa1-xSemiconductor on N emission layers
Superficial layer；
Wherein, the material of the semiconductor surface layer is the semi-conducting material of energy gap≤2.3eV at room temperature, the p-type
AlxGa1-xX scope is 0≤x ＜ 1 in N emission layers.
2. photocathode according to claim 1, it is characterised in that the material of the semiconductor surface layer is n-type, intrinsic
Or the iii-v crystalline material of p-type.
3. photocathode according to claim 2, it is characterised in that the material of the semiconductor surface layer is p-type III-V
Group crystal material, foreign atom are Zn or Be, doping concentration≤1 × 1020cm-3。
4. photocathode according to claim 2, it is characterised in that the material of the semiconductor surface layer is n-type III-V
Group crystal material, foreign atom Si, Sn, Ge, C, Te or S, doping concentration≤1 × 1020cm-3。
5. according to any described photocathode of Claims 1 to 4, it is characterised in that the thickness h of the semiconductor surface layer
Scope is 0<h≤200nm.
6. according to any described photocathode of Claims 1 to 4, it is characterised in that the doping of the p-type AlN cushions is former
Son is Mg, doping concentration≤1 × 1019cm-3。
7. according to any described photocathode of Claims 1 to 4, it is characterised in that the p-type AlxGa1-xN emission layers are mixed
Hetero atom is Mg, and concentration gradient number is m, and m >=1, doping concentration from semiconductor surface layer toward p-type AlN cushions direction successively
For N1、N2、…、Nm-1、Nm, and meet 1 × 1015cm-3≤N1≤N2≤…≤Nm-1≤Nm≤1×1020cm-3。
8. according to any described photocathode of Claims 1 to 4, it is characterised in that the p-type AlxGa1-xN emission layers include n
Individual p-type AlxGa1-xN sublayers, wherein n >=1, from semiconductor surface layer toward each layer of direction of p-type AlN cushions p-type AlxGa1-xN
The Al components of layer are followed successively by x1、x2、…、xn-1、xn, and meet 0≤x1≤x2≤…≤xn-1≤xn＜ 1.
9. a kind of preparation method of photocathode, it is characterised in that comprise the following steps：P-type AlN bufferings are formed on substrate
Layer, p-type Al is formed on p-type AlN cushionsxGa1-xN emission layers, in p-type AlxGa1-xSemiconductor surface is formed on N emission layers
Layer, obtains photoelectric cathode materials；Line activating is entered to photoelectric cathode materials, obtains photocathode.
10. the preparation method of a kind of photocathode according to claim 9, it is characterised in that the active mode is to move back
Fire activation.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108649076A (en) * | 2018-05-15 | 2018-10-12 | 中国电子科技集团公司第五十五研究所 | Change Al component transmission-type GaAlAs photocathodes with ultra-thin GaAs emission layers |
| CN111370276A (en) * | 2018-12-26 | 2020-07-03 | 中国电子科技集团公司第十二研究所 | Vacuum channel type photoelectric cathode and preparation method thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3953880A (en) * | 1973-06-28 | 1976-04-27 | Hamamatsu Terebi Kabushiki Kaisha | Semiconductor photoelectron emission device |
| US4749903A (en) * | 1985-11-29 | 1988-06-07 | Thomson Csf | High-performance photocathode |
| JPS63239869A (en) * | 1986-11-20 | 1988-10-05 | Nec Corp | Photodetector |
| JPH04348084A (en) * | 1991-02-13 | 1992-12-03 | Ricoh Co Ltd | Light functional element |
| CN1632898A (en) * | 2003-12-24 | 2005-06-29 | 中国科学院半导体研究所 | Middle concentration P-type doping transmission type gallium arsenide optical cathode material and method for preparing same |
| JP2009048837A (en) * | 2007-08-17 | 2009-03-05 | Kyushu Univ | Organic electroluminescence element and organic laser diode |
| CN102254779A (en) * | 2011-05-10 | 2011-11-23 | 中国电子科技集团公司第五十五研究所 | Cs-activation-free heterojunction type GaN negative electron affinity photoelectric cathode |
| CN207441648U (en) * | 2017-12-06 | 2018-06-01 | 中国电子科技集团公司第十二研究所 | A kind of photocathode |
-
2017
- 2017-12-06 CN CN201711272587.1A patent/CN107895681A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3953880A (en) * | 1973-06-28 | 1976-04-27 | Hamamatsu Terebi Kabushiki Kaisha | Semiconductor photoelectron emission device |
| US4749903A (en) * | 1985-11-29 | 1988-06-07 | Thomson Csf | High-performance photocathode |
| JPS63239869A (en) * | 1986-11-20 | 1988-10-05 | Nec Corp | Photodetector |
| JPH04348084A (en) * | 1991-02-13 | 1992-12-03 | Ricoh Co Ltd | Light functional element |
| CN1632898A (en) * | 2003-12-24 | 2005-06-29 | 中国科学院半导体研究所 | Middle concentration P-type doping transmission type gallium arsenide optical cathode material and method for preparing same |
| JP2009048837A (en) * | 2007-08-17 | 2009-03-05 | Kyushu Univ | Organic electroluminescence element and organic laser diode |
| CN102254779A (en) * | 2011-05-10 | 2011-11-23 | 中国电子科技集团公司第五十五研究所 | Cs-activation-free heterojunction type GaN negative electron affinity photoelectric cathode |
| CN207441648U (en) * | 2017-12-06 | 2018-06-01 | 中国电子科技集团公司第十二研究所 | A kind of photocathode |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108649076A (en) * | 2018-05-15 | 2018-10-12 | 中国电子科技集团公司第五十五研究所 | Change Al component transmission-type GaAlAs photocathodes with ultra-thin GaAs emission layers |
| CN111370276A (en) * | 2018-12-26 | 2020-07-03 | 中国电子科技集团公司第十二研究所 | Vacuum channel type photoelectric cathode and preparation method thereof |
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