JPS6329241A - Method for evaluating electrical conductivity by ultraviolet light electron spectroscopy - Google Patents

Method for evaluating electrical conductivity by ultraviolet light electron spectroscopy

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Publication number
JPS6329241A
JPS6329241A JP61173137A JP17313786A JPS6329241A JP S6329241 A JPS6329241 A JP S6329241A JP 61173137 A JP61173137 A JP 61173137A JP 17313786 A JP17313786 A JP 17313786A JP S6329241 A JPS6329241 A JP S6329241A
Authority
JP
Japan
Prior art keywords
sample
electrical conductivity
threshold value
photoelectrons
conductivity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP61173137A
Other languages
Japanese (ja)
Inventor
Satoshi Asada
聡 浅田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Priority to JP61173137A priority Critical patent/JPS6329241A/en
Publication of JPS6329241A publication Critical patent/JPS6329241A/en
Pending legal-status Critical Current

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  • Analysing Materials By The Use Of Radiation (AREA)
  • Measurement Of Resistance Or Impedance (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

PURPOSE:To judge the electrical conductivity of a material by changing the blocking electric field for photoelectron and determining the threshold value of the energy of ionization of a sample. CONSTITUTION:The sample 6 is disposed as a photoelectric cathode in a vacuum vessel 1 the inside of which is evacuated by a vacuum pump 2. UV rays are projected from a light source 3 through a shutter 4 and the released photoelectrons are collected by a collector electrode 5 and are detected by a microammeter 8. A variable voltage source 7 for scanning by varying the blocking electric field for the photoelectrons is connected to the sample 6. The detected photoelectric source is differentiated to a differential waveform by a prescribed differentiation circuit, by which the energy distribution curve of the photoelectrons is obtd. The material is thus capable of having the electrical conductivity at the molecular level if the threshold value of the energy of ionization of certain material is about <=6.5eV.

Description

【発明の詳細な説明】 [産業上の利用分野] =  1  = 本発明は、紫外線光電子分光法によって試料の光電子ス
ペクトルを測定し、該試料の分子レベルでの導電性を評
(111する方法に関する。
Detailed Description of the Invention [Industrial Application Field] = 1 = The present invention relates to a method for measuring the photoelectron spectrum of a sample by ultraviolet photoelectron spectroscopy and evaluating the conductivity of the sample at the molecular level. .

ここに、分子レベルでの導電性の評価とは、該試料を成
す材料が、本来的に導電性を有するか否かを評価するこ
とをいう。
Here, the evaluation of conductivity at the molecular level refers to evaluating whether the material forming the sample inherently has conductivity.

[従来の技術] 従来、成る試料の電気伝導度は、例えば四端子法等を用
いて、該試料に現実に通電してその入出力電圧、及び/
または、電流を測定し、それらの関係より求めでいた。
[Prior Art] Conventionally, the electrical conductivity of a sample has been measured by actually applying current to the sample and measuring its input/output voltage and/or using the four-probe method, for example.
Alternatively, it could be determined by measuring the current and using the relationship between them.

換言すれば、材料一般ではなく、特定の試料そのしのの
電気抵抗を巨視的に求めていた。
In other words, the electrical resistance of a specific sample, rather than the material in general, was determined macroscopically.

まIC、従来、試料に紫外線を照射して光電子を放出せ
しめ、該試料の光電子スペクトルを測定して各種の情報
を得る方法(紫外線光電子分光法;UPS)が、行なわ
れている。
Conventionally, an IC method (ultraviolet photoelectron spectroscopy; UPS) has been used in which a sample is irradiated with ultraviolet rays to cause it to emit photoelectrons, and the photoelectron spectrum of the sample is measured to obtain various information.

[発明が解決しにうとする問題点〕 上記した従来の電気伝導度の測定方法は、成る月料一般
の電気伝導性を評価することができないという問題点を
有する。
[Problems to be Solved by the Invention] The conventional electrical conductivity measuring method described above has a problem in that it is not possible to evaluate the electrical conductivity of monthly charges in general.

即ち、試料の電気伝導度は、たとえ同一の材料から成る
試料であっても、結晶状態、測定環境等の相違によって
、変化する。例えば、アモルファス状態では導電性を示
さない材料であっても、単結晶状態ではS電性を示す場
合がある。
That is, the electrical conductivity of a sample changes depending on the crystal state, measurement environment, etc., even if the sample is made of the same material. For example, even if a material does not exhibit conductivity in an amorphous state, it may exhibit S conductivity in a single crystal state.

このため、成る材料が本来的に導電性を有するか否かを
知るためには、場合によっては、結晶状態等の異なる個
々の試料について、それぞれ測定環境等を変えて電気伝
導度を測定しなければならず、手間及び時間を要した。
Therefore, in order to know whether or not a material is inherently conductive, it may be necessary to measure the electrical conductivity of individual samples with different crystal states under different measurement environments. However, it took a lot of effort and time.

また、材料によっては、所望の結晶状態等の試料を得る
ことが困難なものもあ−)だ。
Furthermore, depending on the material, it may be difficult to obtain samples with the desired crystalline state.

さらにまた、そのようにして測定したとしても、全ての
状態、あるいは全ての環境条件を網羅できるものでもな
かった。
Furthermore, even when measured in this way, it is not possible to cover all states or all environmental conditions.

本発明は、かかる事情に鑑み案出されたものであり、成
る材料が導電性を有し得るか否かを容易に評価し得る方
法を提供するものである。
The present invention has been devised in view of the above circumstances, and provides a method for easily evaluating whether or not a material is electrically conductive.

[問題点を解決するための手段及び作用〕本発明は、 試料に紫外線を照射して光電子を放出せしめ、該試料の
光電子スペクトルを測定して評価する方法に於いて、 前記光電子に対する阻止電場を変化させて、光電子放出
の始まる電圧値より前記試料のイオン化エネルギーのし
きい値を求め、 該しきい値より前記試料の導電性を評価することを特徴
とする方法である。
[Means and effects for solving the problems] The present invention provides a method for emitting photoelectrons by irradiating a sample with ultraviolet rays, and measuring and evaluating the photoelectron spectrum of the sample, which includes the following steps: This method is characterized in that the threshold value of the ionization energy of the sample is determined from the voltage value at which photoelectron emission starts, and the conductivity of the sample is evaluated from the threshold value.

換言すると、本発明は、イオン化エネルギーのしきい値
によって分子レベルでの導電性を評価し得るという知見
、即ち、成る特定材料のイオン化エネルギーのしきい値
が、成る値(約6.5eV)以下であれば、該材料の結
晶状態あるいはドープ材料等を変えることにより、該材
料に導電性を持たせ得るという知見に基づくものである
In other words, the present invention is based on the knowledge that conductivity at the molecular level can be evaluated based on the threshold value of ionization energy, that is, the threshold value of ionization energy of a specific material is less than or equal to the value (approximately 6.5 eV). If so, this is based on the knowledge that conductivity can be imparted to the material by changing the crystalline state of the material or the doping material.

さらに、材料が高分子材料である場合には、各共役電子
系の電子相互作用に関与するπ電子のとり得るエネルギ
ーバンド幅が、導電性の程度に影響するため、該バンド
幅を前記評価のデータとして加味することにより、導電
性の評価を、より詳細に行なうことがて゛きる。
Furthermore, when the material is a polymeric material, the possible energy band width of the π electrons involved in the electronic interaction of each conjugated electron system affects the degree of conductivity. By taking this into account as data, conductivity can be evaluated in more detail.

なお、上記した2つの事情(イオン化エネルギー、及び
、π電子に関ブる事情)は、電気伝導度σを、 σ−enμ (e:素電葡量、n:キャリ7’fA度、μ:キャリア
移動度) とする式に於いて、イオン化エネルギーのしきい値がn
に、また、π電子のバンド幅が11に、それぞれ影響す
るものとして表現される。
Note that the above two circumstances (related to ionization energy and π electrons) change the electrical conductivity σ to σ-enμ (e: elementary electric capacity, n: carry 7'fA degrees, μ: carrier mobility), the threshold value of ionization energy is n
, and the band width of π electrons is expressed as having an influence on 11.

[実施例] 以下、本発明を実施例に基づいて説明する。[Example] Hereinafter, the present invention will be explained based on examples.

第1図は、紫外線光電子分光法により試料の光電子スペ
クトルを得る装置の模式図である。
FIG. 1 is a schematic diagram of an apparatus for obtaining a photoelectron spectrum of a sample by ultraviolet photoelectron spectroscopy.

図示の装置は、真空ポンプ2にて排気された真空槽1内
に、試料6を光電陰極となるようにして配置し、該試料
6に光源3よりシトツタ4を介して紫外線を照射し、放
出された光電子をコレクタ電極5にて収集して微小電流
計8にて検出するも=  5 − のである。なお、試料6には、光電子に対する阻止電場
を可変してスキャンするための可変電圧源7が接続され
ている。また、図示は省略されているが、検出された光
電流は、所定の微分回路にて微分波形とされ、これより
、光電子のエネルギー分布曲線(UPSスペクトル)を
得る構成とされている。
In the illustrated apparatus, a sample 6 is placed in a vacuum chamber 1 that is evacuated by a vacuum pump 2 so as to act as a photocathode, and the sample 6 is irradiated with ultraviolet light from a light source 3 through a shutter 4 to emit light. The resulting photoelectrons are collected by the collector electrode 5 and detected by the microcurrent meter 8, which is = 5 -. Note that a variable voltage source 7 is connected to the sample 6 for scanning by varying the blocking electric field for photoelectrons. Although not shown in the drawings, the detected photocurrent is converted into a differentiated waveform by a predetermined differentiating circuit, from which a photoelectron energy distribution curve (UPS spectrum) is obtained.

上記装置に於いて真空槽1内の圧力は10−7〜1O−
8Paとされており、また、コレクタ電極5の内表面に
は、金(AU)が蒸着され、光電子の収集効率を高める
ようにされている。なお、紫外線の光源としては、従来
より用いられている水素ガス放電光、稀ガス放電の共鳴
線、あるいはシンクロ1−ロン(SOR)光源等を利用
することができる。
In the above device, the pressure inside the vacuum chamber 1 is 10-7 to 1O-
8 Pa, and gold (AU) is deposited on the inner surface of the collector electrode 5 to increase the photoelectron collection efficiency. Note that as the ultraviolet light source, conventionally used hydrogen gas discharge light, rare gas discharge resonance line, Synchro 1-Ron (SOR) light source, etc. can be used.

第2図は、光源としてHel (hシー21.2eV)
を用い、第1図の装置によって阻止電場をスキャンして
測定した固体ベンゼンのUPSスペクトルであり、第3
図は、SOR光源(hシー33eV)にて測定したポリ
パラフェニレン(PPP)のUPSスペクトルである。
Figure 2 shows Hel (h sea 21.2eV) as a light source.
This is the UPS spectrum of solid benzene measured by scanning the blocking electric field with the apparatus shown in Figure 1.
The figure shows the UPS spectrum of polyparaphenylene (PPP) measured with a SOR light source (hc 33 eV).

図示のように、ベンゼンのイオン化エネルギーPのイオ
ン化エネルギーのしきい値、には5.9eVである。な
お、図に於いて、グラフ十の複数のピークは、それぞれ
、電子の存在確率のピーク単位に対応し、最も右側に位
置覆るピークが最高被占準位に対応する。
As shown in the figure, the threshold value of the ionization energy P of benzene is 5.9 eV. In the figure, the plurality of peaks in graph 10 each correspond to the peak unit of the electron existence probability, and the peak located on the rightmost side corresponds to the highest occupied level.

上記と同様にして、各種ポリマーについてイオン化エネ
ルギーのしきい値、tkをそれぞれ求めるとともに、従
来の方法によって該各種ポリマーの電気伝導度σをそれ
ぞれ測定した。その結果の一部を第4図に示す。
In the same manner as described above, the threshold value of ionization energy, tk, was determined for each type of polymer, and the electrical conductivity σ of each type of polymer was measured using a conventional method. A part of the results are shown in FIG.

第4図に於いて、例えば、ボリパラフJニレンスルフイ
ド(PPS)について見てみると、結晶薄膜(ASFs
ドープ)状態での電気伝導度σは約1O8/Cml!i
!iであるのに対し、非晶質状態では約10−’S/c
lIl程度である。しかし、両者のイオン化エネルギー
のしきい値IJkは、ともに、6eV程度である。即ち
イオン化ユネルギーのし十に きいIff I、  は、結晶状態にかかわらず、材料
が同一分子で構成されていれば、同じ値をとるものであ
る。
In Figure 4, for example, looking at polyparafine sulfide (PPS), crystalline thin films (ASFs)
The electrical conductivity σ in the doped state is approximately 1O8/Cml! i
! i, whereas in the amorphous state it is about 10-'S/c
It is about lIl. However, both ionization energy thresholds IJk are about 6 eV. That is, the maximum ionization energy, If I, takes the same value regardless of the crystal state if the material is composed of the same molecules.

さらに、種類の異なる多数の材料について、イk オン化エネルギーのしきい値IS  と電気伝導度σと
をイれぞれ測定し、両者の関係について評価したところ
、成る材料のイオン化エネルギーのしき七に イ1tiIs  が6.5eVFiI度以下であれば、
結晶状態、及び/または、ドープ材料等を工夫すること
により、@材料に導電性を付与し得ることが判明した。
Furthermore, we measured the ionization energy threshold IS and the electrical conductivity σ for a number of different materials, and evaluated the relationship between the two. If nii1tiIs is less than 6.5eVFiI degrees,
It has been found that electrical conductivity can be imparted to the @ material by modifying the crystalline state and/or doping material.

換言すれば、成る材料のイオン化エネルギーのしきイ1
ilIJ、7が6.5eV稈度以下であれば、該材料は
分子レベルでの導電性を有するものとしてよいことがわ
かった。
In other words, the threshold of ionization energy of the material made of
It has been found that if ilIJ,7 is 6.5 eV or less, the material may have conductivity at the molecular level.

また、ポリマーについては、イオン化エネルギk −のしきい値1g  と、最高被占準位(例えば、第2
図、第3図等に於いて、最も右側のピークに対応覆るエ
ネルギー準位)とから、各ベンゼン環の電子相互作用に
関与するπ電子のエネルギーバンド幅を決定することに
より、期待し得る導電性の程度に関する、より詳細な知
見を得た。
In addition, for polymers, the threshold value of ionization energy k − 1g and the highest occupied level (e.g., the second
By determining the energy band width of the π electrons involved in the electronic interaction of each benzene ring from the energy level corresponding to the rightmost peak in Figure 3, etc., the expected conductivity can be determined. We obtained more detailed information regarding the degree of sexual activity.

[効果] 以上、詳述したように本発明は、成る特定材料のイオン
化エネルギーのしきい値が、成る値〈約6.5eV)以
下であれば、該材料の結晶状態あるいはドープ材料等を
変えることにより、該材料に導電性を持たせ19るとい
う知見に基づいて成されたものであり、UPSを用いて
前記イオン化エネルギーのしきい値を求め、材料の導電
性を判断するものである。
[Effect] As detailed above, the present invention changes the crystalline state of the material or the doped material, etc., if the ionization energy threshold of the specific material is less than or equal to the value (approximately 6.5 eV). This was done based on the knowledge that this makes the material conductive19, and the ionization energy threshold is determined using UPS to determine the conductivity of the material.

実施例に述べたように、本発明によると、試料の結晶状
態、あるいは測定環境等にかかわらず、分子レベルでの
導電性を判断づることができる。
As described in the Examples, according to the present invention, conductivity at the molecular level can be determined regardless of the crystal state of the sample or the measurement environment.

したがって、導電性を有する材料の選定が容易である。Therefore, it is easy to select a conductive material.

また、測定がスペクト日スコピックな手払であり、測定
に際して同一の試料を繰り代えし使用できるため、測定
精度の向上が期待できる。
In addition, since measurements are performed manually and spectroscopically, and the same sample can be used repeatedly during measurements, improved measurement accuracy can be expected.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は実施例で用いたUPS測定装置の構成を示す模
式図である。第2図はベンゼンの光電子スペク1−ルを
、また、第3図はPPPの光電子スペクi〜ルを、それ
ぞれ示す図である。第4図はイオン化エネルギーのしぎ
い値と電気伝導度との関係を示寸図である。
FIG. 1 is a schematic diagram showing the configuration of the UPS measuring device used in the example. FIG. 2 shows the photoelectron spectrum of benzene, and FIG. 3 shows the photoelectron spectrum of PPP. FIG. 4 is a dimensional diagram showing the relationship between the threshold value of ionization energy and electrical conductivity.

Claims (2)

【特許請求の範囲】[Claims] (1)試料に紫外線を照射して光電子を放出せしめ、該
試料の光電子スペクトルを測定して評価する方法に於い
て、 前記光電子に対する阻止電場を変化させて、光電子放出
の始まる電圧値より前記試料のイオン化エネルギーのし
きい値を求め、 該しきい値より前記試料の導電性を評価することを特徴
とする方法。
(1) In the method of emitting photoelectrons by irradiating the sample with ultraviolet rays and measuring and evaluating the photoelectron spectrum of the sample, the blocking electric field for the photoelectrons is changed to increase the voltage value at which photoelectron emission starts from the sample. A method characterized by: determining an ionization energy threshold value, and evaluating the conductivity of the sample from the threshold value.
(2)前記特許請求の範囲第1項に於いて、前記試料は
高分子材料であり、 前記光電子スペクトルのピークより最高被占準位を求め
、該最高被占順位と前記しきい値とよりπ電子のエネル
ギーバンド幅を求め、前記導電性評価のデータとして加
味する方法。
(2) In claim 1, the sample is a polymer material, the highest occupied level is determined from the peak of the photoelectron spectrum, and the highest occupied level is determined from the threshold value. A method of determining the energy band width of π electrons and adding it to the data for the conductivity evaluation.
JP61173137A 1986-07-23 1986-07-23 Method for evaluating electrical conductivity by ultraviolet light electron spectroscopy Pending JPS6329241A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP61173137A JPS6329241A (en) 1986-07-23 1986-07-23 Method for evaluating electrical conductivity by ultraviolet light electron spectroscopy

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP61173137A JPS6329241A (en) 1986-07-23 1986-07-23 Method for evaluating electrical conductivity by ultraviolet light electron spectroscopy

Publications (1)

Publication Number Publication Date
JPS6329241A true JPS6329241A (en) 1988-02-06

Family

ID=15954802

Family Applications (1)

Application Number Title Priority Date Filing Date
JP61173137A Pending JPS6329241A (en) 1986-07-23 1986-07-23 Method for evaluating electrical conductivity by ultraviolet light electron spectroscopy

Country Status (1)

Country Link
JP (1) JPS6329241A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0294475A (en) * 1988-09-29 1990-04-05 Mitsubishi Electric Corp Manufacture of color filter
CN103226167A (en) * 2013-04-24 2013-07-31 兰州空间技术物理研究所 Conductivity measurement device and method of dielectric material

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0294475A (en) * 1988-09-29 1990-04-05 Mitsubishi Electric Corp Manufacture of color filter
CN103226167A (en) * 2013-04-24 2013-07-31 兰州空间技术物理研究所 Conductivity measurement device and method of dielectric material

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