# US 11,906,456 B2 · Sensor element, sensor device, sensor system and detection method

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- Number: US 11,906,456 B2
- Document ID: US11906456B2
- Status: Granted
- Kind: B2
- Application number: 17/204,512
- Filed: 2021-03-17
- Published: 2022-03-17
- Granted: 2024-02-20
- Earliest claimed: 2020-09-17
- Assignees: Kabushiki Kaisha Toshiba
- Applicants: Kabushiki Kaisha Toshiba
- Inventors: Yoshiaki Sugizaki
- Web page: https://patentgrep.com/patent/US11906456B2

## CPC

- G01N 27/122: {Circuits particularly adapted therefor, e.g. linearising circuits}
- G01N 27/125: {Composition of the body, e.g. the composition of its sensitive layer}
- G01N 27/4141: {specially adapted for gases}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

According to one embodiment, a sensor element capable of detecting a target substance contained in an atmosphere is disclosed. The sensor includes a graphene, a drain electrode provided on the graphene, a source electrode adhered to the graphene, and a first substance provided on the graphene and having a charge condition. The charge condition is changed when irradiation of light and stopping of the irradiation of the light are performed. The target substance is detectable by measuring current that flows between the source electrode and the drain electrode. The measuring of the current is performed in a period during which the irradiation of the light and the stopping of the irradiation of the light are repeated above the sensor element.

## Claims

### Claim 1

A sensor element capable of detecting a target substance contained in an atmosphere, the sensor element comprising:
a graphene;
a drain electrode provided on the graphene;
a source electrode provide on the graphene;
a first substance provided on the graphene and having a charge condition and including carboxyl group, phosphate group, sulfonic group, silanol group, hydroxyl group, or amino group, wherein the charge condition is changed when irradiation of light and stopping of the irradiation of the light are performed; and
a humidification mechanism configured to humidify the atmosphere,
the target substance being detectable by measuring current that flows between the source electrode and the drain electrode, the measuring of the current being performed in a period during which the irradiation of the light and the stopping of the irradiation of the light are repeated above the sensor element, and
the measuring of the current being performed after the atmosphere is humidified by the humidification mechanism.

### Claim 2 (depends on 1)

The sensor element of claim 1, wherein:
the current in the period differs in a first case and a second case,
the first case is that the sensor element is subjected to the atmosphere containing the target substance, and
the second case is that the sensor element is subjected to the atmosphere not containing the target substance.

### Claim 3 (depends on 1)

The sensor element of claim 1, wherein:
the first substance includes a substance capable of inducing charge transfer between the graphene and the first substance, or a metal particle.

### Claim 4 (depends on 1)

The sensor element of claim 1, wherein:
the current in a period during which the light is irradiated and the current in a period during which the light is not irradiated in a case where the sensor element is subjected to the atmosphere containing the target substance is different from the current in the period during which the light is irradiated and the current in the period during which the light is not irradiated in a case where the sensor element is subjected to the atmosphere not containing the target substance.

### Claim 5 (depends on 1)

The sensor element of claim 1, wherein:
a difference between a value of the current in a period during which the light is irradiated and a value of the current in a period during which the light is not irradiated are different between a third case and a fourth case,
the third case is that the graphene and the first substance are subjected to the atmosphere containing the target substance, and
the fourth case is that the graphene and the first substance are subjected to the atmosphere not containing the target substance.

### Claim 6 (depends on 1)

The sensor element of claim 1, further comprising a gate electrode for applying a voltage to the graphene.

### Claim 7 (depends on 6)

The sensor element of claim 6, further comprising: one of gold, platinum, silver and silver chloride, provided on a surface of the gate electrode.

### Claim 8 (depends on 6)

The sensor element of claim 6, further comprising: a conductive layer provided between the gate electrode and the graphene.

### Claim 9 (depends on 8)

The sensor element of claim 8, wherein:
an electric resistance between the gate electrode and the graphene is between 10 MΩ and 100 GΩ.

### Claim 10 (depends on 1)

The sensor element of claim 1, further comprising: a second substance provided to at least one of the first substance, the graphene and the conductive layer, and configured to be specifically bonded to the target substance.

### Claim 11 (depends on 1)

The sensor element of claim 1, wherein:
the target substance is one of a sulfide compound, limonene, methyl benzoate, ecgonine derivative, methamphetamine, amphetamine, caryophyllene and a derivative thereof, heliotropin and 3, 4-methylene dioxyphenylpropane-2-one (MDP2P).

### Claim 12 (depends on 1)

A sensor device comprising:
a sensor element of claim 1;
a measurement unit configured to measure a current flowing between a source electrode and a drain electrode of the sensor element; and
a judgement unit configured to judge one of presence or absence of the target substance and a concentration of the target substance.

### Claim 13 (depends on 12)

The sensor device of claim 12, wherein the sensor element includes a gate electrode, and
further comprising: a gate voltage control unit configured to control a gate voltage applied to the gate electrode based on the current measured by the measurement unit.

### Claim 14 (depends on 13)

The sensor device of claim 13, wherein:
the gate voltage control unit configured to adjust the gate voltage such that a value of the current flowing between the source electrode and the drain electrode of the sensor element falls in a predetermined range, and
the value of the current is a first value of the current at a time of light irradiation, a second value of the current at a time of stopping the light, or an average value of the first value and the second value.

### Claim 15 (depends on 13)

A sensor system comprising:
a sensor unit including a sensor device of claim 13;
a humidification unit configured to humidify gas that potentially contains a target substance; and
an irradiation unit which irradiates light to the sensor device.

### Claim 16 (depends on 15)

The sensor system of claim 15, wherein:
the irradiation unit comprises a light source, and a light blinking control unit connected to the light source and configured to control blinking of light generated by the light source.

### Claim 17 (depends on 15)

The sensor system of claim 15, further comprising:
a pipe configured to connect the humidifying unit and the sensor unit to each other and supply the humidified gas to a sensor element of the sensor device.

### Claim 18 (depends on 15)

The sensor system of claim 15, wherein:
the sensor device detects one of a sulfide compound, limonene, methyl benzoate, ecgonine derivative, methamphetamine, amphetamine, caryophyllene, a derivative of amphetamine, caryophyllene, derivative of caryophyllene, heliotropin and 3, 4-methylene dioxyphenylpropane-2-one (MDP2P).

### Claim 19 (depends on 1)

A detection method employing a sensor element of claim 1, the method comprising:
repeating irradiation of light and stopping thereof above a graphene of the sensor element;
humidifying a gas that potentially contains a target substance;
supplying the humidified gas to the sensor element;
measuring a current flowing between the a source electrode and a drain electrode of the sensor unit; and
judging one of presence or absence of the target substance and concentration of the target substance based on the measured current.

### Claim 20 (depends on 19)

The sensing method of claim 19, further comprising applying voltage to the graphene such that a value of the current flowing between the source electrode and the drain electrode of the sensor element falls in a predetermined range, and
the value of the current is a first value of the current at a time of light irradiation, a second value of the current at a time of stopping the light, or an average value of the first value and the second value.