CN1724983A - The fast response broad band laser detector that utilizes oxide heterojunction material to make - Google Patents

Abstract

The invention relates to a fast-response broadband laser detector made of oxide heterojunction materials, comprising: a strontium niobate-doped titanate substrate, and a doped lanthanum manganate thin film layer epitaxially grown thereon to form a niobium-doped strontium titanate substrate Strontium titanate-doped lanthanum manganate oxide heterojunction; or an insulating layer is epitaxially grown on a strontium niobate-doped titanate single crystal substrate, and a doped lanthanum manganate film is epitaxially grown on the insulating layer to form niobium-doped titanium strontium oxide-insulating layer-doped lanthanum manganate oxide heterojunction; the first electrode is set on the doped lanthanum manganate film, the second electrode is set on the bottom, and one end of the two electrode leads is respectively connected to the first electrode and the The second electrode is connected, and the other end of the electrode lead is a signal output end. When the light irradiates the laser detector, a voltage signal is generated directly, without any auxiliary power supply and electronic circuit. Its response band ranges from ultraviolet to far infrared, and can respond to laser pulses with femtosecond pulse width. The leading edge of the voltage pulse generated by the laser pulse is less than 1.5ns, the half width is less than 2ns, and the full pulse width is only a few ns.

Description

Fast Response Broadband Laser Detector Made of Oxide Heterojunction Materials

technical field

The invention relates to a laser detector, in particular to a fast-response broadband laser detector made of oxide heterojunction materials.

Background technique

The detection of laser energy, power, pulse width and waveform is not only very important for laser devices and scientific research, but also has a very wide range of applications in military, national defense, production and life. Although people have developed many different types of laser detectors such as pyroelectricity, photoelectricity, pyroelectricity, etc., the work for novel laser detectors is still people's interest and ongoing work, and the applicant is also in this regard Obtained the following patents for laser detectors, such as patent number: ZL89202869.6; patent number: ZL89220541.5; patent number: ZL90202337.3, patent number: ZL90205920.3; Made of electrical materials, the photoresponse of the detector is not fast enough, and the response band is not wide enough.

The magnetoresistance properties of doped lanthanum manganate materials have been studied a lot, and recently people have also observed the photoelectric properties of doped lanthanum manganate films (such as literature 1, Time dependence of laser-inducedthermoelectric voltages in La _1-x Ca _x MnO ₃ and YBa ₂ Cu ₃ O _7-δ thin films, PX Zhang et al., Appl. Phys. Lett., Vol.84, No.21, 4026 (2002)), but the pulse width of its photoresponse is on the order of ms, Therefore, it cannot be used to detect and measure pulsed laser waveforms with a laser pulse width less than ms.

Contents of the invention

The object of the present invention is to overcome the defects of slow photoresponse speed and narrow response band of the above-mentioned detector; to provide a voltage signal directly generated after light irradiation without any auxiliary power supply and electronic circuit; to detect the energy, power and Waveform, its response band is from ultraviolet to far infrared, it can respond to laser pulse with femtosecond pulse width, the half width of generated voltage pulse can be less than 2ns, the full width of pulse can reach several ns, and it is made of oxide heterojunction material Fast response broadband laser detector.

The purpose of the present invention is achieved like this:

The fast-response broadband laser detector made of oxide heterojunction materials provided by the present invention includes: a shell, a substrate 1 made of a strontium niobate-doped titanate single crystal, on which a photoresponsive material layer 2 is epitaxially grown. chip, a first electrode 3, a second electrode 4 and a lead 6; it is characterized in that: the photoresponsive layer 2 is a doped lanthanum manganate thin film epitaxially grown on a strontium niobate-doped titanate single crystal substrate 1 layer 2, forming a strontium niobate titanate-doped lanthanum manganate oxide heterojunction; or epitaxially growing an insulating layer 7 on a strontium niobate titanate single crystal substrate 1, and doping a lanthanum manganate thin film 2 epitaxially growing On the insulating layer 7, a heterojunction of doped strontium niobate titanate-insulating layer-doped lanthanum manganate oxide is formed; the first electrode 3 is arranged on the doped lanthanum manganate film 2, and the second electrode 4 is arranged on the On the strontium titanate single crystal substrate 1, one end of the two electrode leads 6 is respectively connected to the first electrode 3 and the second electrode 4, and the other end of the electrode leads 6 is a signal output end; or it is installed in a metal shell , The metal casing plays a shielding role against external electromagnetic interference.

It also includes a resistor 5, the two ends of the resistor 5 are respectively connected to the output ends of the two electrode leads 6, and its resistance value is 0.01-1MΩ. The resistor 5 is mainly for improving the response speed. Since the structure of the heterojunction has a capacitive characteristic, the resistor 5 discharges the voltage generated after laser irradiation.

In the strontium niobate titanate-doped SrNb _x Ti _1-x O ₃ single crystal substrate 1 , x is 0.005-0.1.

The insulating layer 7 includes: lanthanum aluminate (LaAlO ₃ ), strontium titanate (SrTiO ₃ ), barium titanate (BaTiO ₃ ), zirconia (ZrO ₂ ), lanthanum manganate (LaMnO ₃ ) or magnesium oxide ( MgO), the thickness of the insulating layer is 1 nm to 500 nm. The doped lanthanum manganate thin film layer 2 is R _1-x A _x MnO ₃ , and the thickness of the doped lanthanum manganate thin film layer 2 is 0.8 nm to 2 μm; wherein R includes: La, Pr, Nd or Sm; wherein A includes: Sr, Ca, Ba, Pb, Sn, Te, Nb, Sb, Ta, Ce or Pr; the value of x is 0.05-0.4.

The electrode 3 can be a point, a line, or a circle surrounding the edge of the doped lanthanum manganate film. The second electrode 4 can be connected to any part of the doped strontium niobate titanate, which can be a point, a line or a plane. The first electrode 3 and the second electrode 4 can be directly soldered with indium or solder, or gold, silver or aluminum electrodes can be vapor-deposited by methods such as vacuum coating or magnetron sputtering.

Whether it is a laser detector with a two-layer structure doped with strontium niobate titanate-doped lanthanum manganate or a laser detector with a three-layer structure doped with strontium niobate titanate-insulating layer-doped lanthanum manganate, the effect on detecting laser is consistent. When the pulsed laser is irradiated on the surface of doped lanthanum manganate film, after the doped lanthanum manganate film absorbs the laser pulse, a voltage signal will be generated between strontium niobate titanate 1 and doped lanthanum manganate 2, this effect Called the photovoltaic effect. Whether it is a two-layer structure or a three-layer structure, there is a junction capacitance between doped strontium niobate titanate and doped lanthanum manganate, so a resistor is connected in parallel between doped strontium niobate titanate 1 and doped lanthanum manganate 2 5. Play the role of discharge, reduce the discharge time and eliminate the influence of junction capacitance on the response speed. If the width of the pulse voltage signal generated by the pulsed laser is not considered, the resistor 5 may not be connected.

The fast-response broadband laser detector made of oxide heterojunction materials provided by the present invention has the advantage that it can use film-making methods such as laser molecular beam epitaxy, pulsed laser deposition, magnetron sputtering and viscose method. The doped lanthanum manganate and the insulating layer and the doped lanthanum manganate are directly epitaxially grown on the doped strontium niobate titanate substrate, and the preparation method is simple. The laser detectors are all photovoltaic photodetectors, which directly generate voltage signals when light is irradiated, without any auxiliary power supply and electronic circuits. It can detect various laser parameters such as laser energy, laser power, and laser pulse waveform. Its response band is from ultraviolet to far infrared, and it is a fast-response broadband laser detector. The detection process is an ultra-fast process. The leading edge of the pulse voltage signal generated by photovoltaics is less than 1.5ns, the half width is less than 2ns, and the full pulse width is only a few ns. It can not only detect laser energy with femtosecond pulse width, but also detect ns Pulse width of the laser waveform. A mJ laser pulse can generate a voltage signal of hundreds of mV, which has high sensitivity. Therefore, the heterojunction laser detector doped with strontium niobate titanate and doped lanthanum manganate oxide provided by the present invention is widely used in military affairs, national defense, scientific research, production and life.

Description of drawings

Figure 1. Laser detector with strontium niobate titanate-doped lanthanum manganate two-layer structure.

Figure 2. A laser detector with a three-layer structure of strontium niobate titanate-insulating layer-doped lanthanum manganate.

Figure 3. The La _0.7 Sr _0.3 MnO ₃ /SrNb _0.01 Ti _0.99 O ₃ two-layer structure laser detector was stored and recorded with a 500M oscilloscope, and the voltage signal generated by the YAG laser output wavelength 1.06μm and pulse width 25ps laser pulse was measured.

Figure 4. La _0.7 Sr _0.3 MnO ₃ /SrTiO ₃ /SrNb _0.01 Ti _0.99 O ₃ three-layer structure laser detector is stored and recorded with a 500M oscilloscope, and the output wavelength of the YAG tripled laser is 355nm, and the pulse width is 15ps. voltage signal.

The illustrations are as follows:

1-doped strontium niobate titanate substrate; 2-photoresponsive material layer; 3-first electrode;

4-second electrode; 5-resistance; 6-electrode lead;

7- Insulation layer.

Detailed ways

Example 1

Referring to Figure 1, a laser detector with a two-layer structure doped with strontium niobate titanate-doped lanthanum manganate is prepared, and the following is combined with the specific preparation process to describe the fast-response broadband laser detector made of oxide heterojunction materials according to the present invention The structure is described in detail:

Select laser molecular beam epitaxy equipment, the substrate is 1×1cm ² SrNb _0.01 Ti _0.99 O ₃ doped strontium niobate titanate 1, and directly epitaxially grow a 300nm thick La _0.7 Sr _0.3 MnO ₃ photoresponsive material layer 2 on it to form La _0.7 Sr _0.3 MnO ₃ /SrNb _0.01 Ti _0.99 O ₃ two-layer oxide heterostructure sample, use 1×0.5cm ² La _0.7 Sr _0.3 MnO ₃ /SrNb _0.01 Ti _0.99 O ₃ sample as the detector core; The surface of strontium niobate titanate is welded with the second electrode 4 of about φ2mm, and the first electrode 3 of about φ1mm is welded with indium on the surface of one corner of the La _0.7 Sr _0.3 MnO ₃ film; two copper wires of φ0.1mm are used as electrodes lead wire 6, and weld one end of two φ0.1mm copper electrode lead wires 6 to the first electrode 3 and the second electrode 4 respectively with indium; choose a resistor of 2Ω as the resistor 5, and connect its two ends to the two electrode lead wires respectively The output end of 6 is welded; in this way, the detector core is just prepared, and the detector core is packed into an aluminum detector shell, and the output end is led out with a coaxial cable connector.

Choose a 500M oscilloscope and use the above-mentioned La _0.7 Sr _0.3 MnO ₃ /SrNb _0.01 Ti _0.99 O ₃ two-layer oxide heterojunction laser detector to measure the laser pulse output by the YAG laser with a wavelength of 1.06 μm and a pulse width of 25 ps. Figure 3 is Use an oscilloscope to store and record the voltage signal waveform generated by a laser pulse of the detector.

The rising time of the leading edge of the voltage signal is only ~1.5ns, the half width is only ~2ns, and the laser energy of 1mJ can reach a voltage signal of hundreds of mV. Therefore, the detector is not only an ultrafast process, but also very sensitive.

Example 2

Using laser molecular beam epitaxy equipment, a 100nm-thick La _0.7 Sr _0.3 MnO ₃ thin film photoresponsive material layer 2 was directly epitaxially grown on a SrNb _0.1 Ti _0.9 O ₃ substrate 1 with a diameter of φ25mm to prepare La _0.7 Sr _0.3 MnO ₃ /SrNb _{The 0.1} Ti _0.9 O ₃ two-layer heterostructure sample is used as a chip, and a sample with a diameter of φ25mm is used as a chip, and a silver electrode 3 with a width of 0.5 mm is prepared on the outer circle of the La _0.7 Sr _0.3 MnO ₃ film 2 by magnetron sputtering, SrNb A circular silver electrode 4 with a diameter of 10 mm was prepared in the center of the _0.1 Ti _0.9 O ₃ substrate 1 , and the assembly was the same as that of the laser detector with a two-layer structure prepared in Example 1.

Example 3

A laser molecular beam epitaxy device is selected, manufactured according to Example 1, and an 800nm-thick La _0.95 Ba _0.05 MnO ₃ film photoresponsive material layer 2 is epitaxially grown on a 1×1 cm ² SrNb _0.005 Ti _0.995 O ₃ substrate 1 to form a La _0.95 Ba _0.05 MnO ₃ /SrNb _0.005 Ti _0.995 O ₃ two-layer heterostructure chip, on one edge of the La _0.95 Ba _0.05 MnO ₃ thin film layer, vacuum-deposit a 0.5 mm wide platinum first electrode 3, and the rest are the same as in the embodiment 1, the structure of the fast-response broadband laser detector made of oxide heterojunction materials is the same.

Example 4

A laser molecular beam epitaxy device is used to epitaxially grow an 800nm-thick La _0.6 Ca _0.4 MnO ₃ thin film photoresponsive material layer 2 on a 1×1cm ² SrNb _0.07 Ti _0.93 O ₃ substrate 1 to form a La _0.6 Ca _0.4 MnO ₃ /SrNb _0.07 Ti _0.93 O ₃ two-layer heterostructure chip, on one edge of the La _0.6 Ca _0.4 MnO ₃ film layer, use a magnetron sputtering device to sputter a 0.5mm wide silver first electrode 3, and use a SrNb _0.07 Ti _0.93 O ₃ lining A silver second electrode 4 with a diameter of φ5mm is prepared by magnetron sputtering at the central position above the bottom 1, and the rest is the same as the structure of the fast-response broadband laser detector made of oxide heterojunction materials prepared in Example 1.

Example 5

Laser molecular beam epitaxy equipment was used to directly epitaxially grow a 100nm thick La _0.7 Ce _0.3 MnO ₃ thin film photoresponsive material layer 2 on a 1×1cm ² SrNb _0.07 Ti _0.93 O ₃ substrate 1 to prepare a La _0.7 Ce _0.3 MnO ₃ / SrNb _0.07 Ti _0.93 O ₃ two-layer heterostructure chip sample, and the rest of the structure is the same as that of the fast-response broadband laser detector made of heterojunction materials prepared in Example 1.

Example 6

Using laser molecular beam epitaxy equipment, an 800nm thick La _0.75 Pr _0.25 MnO ₃ thin film photoresponsive material layer 2 was epitaxially grown on a 3×3cm ² SrNb _0.01 Ti _0.99 O ₃ substrate 1 to prepare a La _0.75 Pr _0.25 MnO ₃ /SrNb _0.01 Ti _0.99 O ₃ two-layer heterostructure chip, use a 1K resistor purchased from the market as the resistor 5, and the rest are the same as the structure of the fast-response broadband laser detector made of heterojunction materials prepared in Example 1.

Example 7

Laser molecular beam epitaxy equipment was used to directly epitaxially grow a 10nm thick La _0.34 Pr _0.33 Ca _0.33 MnO ₃ film photoresponsive material layer 2 on a 2-inch 2 SrNb _0.1 Ti _0.9 O ₃ substrate 1, La _0.34 Pr _0.33 Ca _0.33 MnO ₃ /SrNb _0.1 Ti _0.9 O ₃ two-layer heterostructure chip, not connected to the resistor 5, and the rest are the same as the structure of the fast-response broadband laser detector made of heterojunction materials prepared in Example 1.

Example 8

Referring to Figure 2, prepare a laser detector with a three-layer structure of doped strontium niobate titanate-insulating layer-doped lanthanum manganate, and combine the specific preparation process as follows: the structure of this embodiment is described in detail, and laser molecular beam epitaxy equipment is selected , _on a 2cm×2cm SrNb _0.1 Ti _0.9 O ₃ substrate 1, first epitaxially 1nm thick SrTiO ₃ as an insulating layer 7, and then epitaxially grow a 300nm thick La _0.7 Sr _0.3 MnO ₃ thin film photoresponsive material layer 2 on SrTiO 3 , forming a La _0.7 Sr _0.3 MnO ₃ /SrTiO ₃ /SrNb _0.1 Ti _0.9 O ₃ three-layer heterostructure chip, cutting it into a detector core with a size of 1×0.5cm ² ; using indium on SrNb _0.1 Ti _0.9 O ₃ The second electrode 4 of about φ2mm is welded on the surface of the substrate 1, and the first electrode 3 of about φ1mm is welded at one corner surface of the La _0.7 Sr _0.3 MnO ₃ film layer 2 with indium; two copper wires of φ0.2mm are used as the Electrode leads 6, and weld one end of two φ0.1mm copper electrode leads 6 to the first electrode 3 and the second electrode 4 respectively with indium; select 0.01Ω wire as resistance 5, and connect its two ends to two The output end of the electrode lead wire 6 is welded; the detector core is just prepared in this way, the detector core is packed in a copper detector shell, and the output end is drawn out with a coaxial cable connector.

A 500M oscilloscope is used to measure the laser pulse output by the YAG tripled frequency laser with a wavelength of 355nm and a pulse width of 15ps with the above-mentioned La _0.7 Sr _0.3 MnO ₃ /SrTiO ₃ /SrNb _0.1 Ti _0.9 O ₃ three-layer laser detector. Figure 4 is the voltage signal waveform generated by storing and recording a laser pulse of the detector with an oscilloscope. It can be seen from Figure 4 that the rising time of the leading edge of the voltage signal generated by the pulsed laser is only ~1ns, the half width is only ~2ns, and the laser energy of 1mJ can produce a voltage signal of hundreds of mV. Therefore, the three-layer detector, like the two-layer detector, is not only an ultrafast process, but also has a high sensitivity.

Example 9

Manufactured according to Example 8, the insulating layer 7 is LaAlO ₃ with a thickness of 500 nm, and the rest of the structure is the same as that of the fast-response broadband laser detector made of heterojunction materials in Example 8.

Example 10

Made according to Example 8, using _BaTiO3 as the insulating layer 7, its thickness is 100nm, and the rest of the structure is the same as that of the fast-response broadband laser detector made of heterojunction materials in Example 8.

Example 11

Made according to Example 8, using _ZrO3 as the insulating layer 7, its thickness is 50nm, and the rest of the structure is the same as that of the fast-response broadband laser detector made of heterojunction materials in Example 8.

Example 12

Manufactured according to Example 8, using MgO as the insulating layer 7 with a thickness of 100 nm, and the rest of the structure is the same as that of the fast-response broadband laser detector made of heterojunction materials in Example 8.

Example 13

Made according to Example 1, the thickness of the La _0.7 Sr _0.3 MnO ₃ photoresponsive material layer 2 is 2 μm, and the rest of the structure is the same as that of the fast-response broadband laser detector made of heterojunction materials in Example 1.

Example 14

Made according to Example 1, using a pulsed laser to prepare the sample, and the rest of the structure is the same as that of the fast-response broadband laser detector made of heterojunction materials in Example 1.

Example 15

Made according to Example 1, using the sample prepared by magnetron sputtering, the rest of the structure is the same as Example 1.

Example 16

Make according to embodiment 1, use the sample prepared by viscose method, all the other structures are the same as embodiment 1.

Example 17

Made according to Example 8, using a sample prepared by a pulsed laser, and the rest of the structure is the same as Example 8.

Example 18

Make according to embodiment 1, resistance 5 adopts 1M resistance, all the other structures are the same as embodiment 1.

Example 19

Made according to Example 1, using La _0.6 Sn _0.4 MnO ₃ as the photoresponsive material layer 2, and the rest are the same as Example 1.

Example 20

Manufactured according to Example 8, using La _0.95 Ba _0.05 MnO ₃ as the photoresponsive material layer 2, and the rest are the same as in Example 8.

Claims (8)

1. fast response broad band laser detector that utilizes oxide heterojunction material to make, comprise: one by on niobium-doped strontium titanate single crystalline substrate (1), the chip that epitaxially grown light responsive material layer (2) makes, first electrode (3), second electrode (4) and lead-in wire (6); It is characterized in that: described photoresponsive layer is the iron-based alloy thin layer (2) of epitaxial growth on niobium-doped strontium titanate single crystalline substrate (1); First electrode (3) is arranged on the iron-based alloy film (2), second electrode (4) is arranged on the niobium-doped strontium titanate single crystalline substrate (1), one end of two contact conductors (6) is connected with second electrode (4) with first electrode (3) respectively, and the other end of contact conductor (6) is a signal output part.

2. by the described fast response broad band laser detector that utilizes heterojunction material to make of claim 1, it is characterized in that: described photoresponsive layer is for going up epitaxial growth one insulation course (7) in niobium-doped strontium titanate single crystalline substrate (1), and iron-based alloy film (2) epitaxial growth is on insulation course (7).

3. by claim 1 or the 2 described fast response broad band laser detectors that utilize heterojunction material to make, it is characterized in that: also comprise a resistance (5), its resistance is 0.01～1M Ω; The two ends of resistance (5) are connected with the signal output part of two contact conductors (6) respectively.

4. by claim 1, the 2 or 3 described fast response broad band laser detectors that each utilizes oxide heterojunction material to make, it is characterized in that: described niobium-doped strontium titanate SrNb _xTi _1-xO ₃Single crystalline substrate (1), its x is 0.005～0.1.

5. by claim 1, the 2 or 3 described fast response broad band laser detectors that each utilizes oxide heterojunction material to make, it is characterized in that: described iron-based alloy thin layer is R _1-xA _xMnO ₃, wherein R comprises: La, Pr, Nd or Sm; A comprises: Sr, Ca, Ba, Pb, Sn, Te, Nb, Sb, Ta, Ce or Pr; Its x value is 0.05～0.4; , the thickness of its iron-based alloy film (2) is 0.8nm～2 μ m.

6. by the described fast response broad band laser detector that utilizes heterojunction material to make of claim 2, it is characterized in that: described insulation course (7) comprising: lanthanum aluminate, strontium titanates, barium titanate, zirconia, lanthanum manganate or magnesium oxide; The thickness of insulation course (7) is 10nm～500nm.

7. by claim 1,2 or 3 described any fast response broad band laser detectors that utilize heterojunction material to make, it is characterized in that: described first electrode (3) comprising: directly weld with indium or scolding tin, or make a point, a line, or around the gold, silver or the aluminium electrode of a circle of iron-based alloy film edge with vacuum coating or magnetically controlled sputter method.

8. by claim 1,2 or 3 described any fast response broad band laser detectors that utilize heterojunction material to make, it is characterized in that: described second electrode (4) is arranged on any position of silicon chip, and second electrode (4) is an indium or scolding tin point directly welding formation, line or face; Or with the electrode of vacuum coating or magnetically controlled sputter method evaporation gold, silver or aluminium.

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