Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications

Advances in Hydrogen Gas Sensor Technology 107

© 2011 by Taylor & Francis Group, LLC

Reference Active

40 µm

300 µm

FIGURE  3.12  Microscopic images of differential sensing diodes. The opening of the active diode was

deposited with 10 nm Pt, and the reference diode was deposited with Ti/Au.

0.08

0.06

Current (A)

I

H

2

–I

air

(A)

0.04

0.02

0.00

0 2 4

Voltage (V)

6 8 10

0.000

0.002

0.004

0.006

0.008

0.010

Active diode

@ 25°C

Air

1% H

2

1

H

2

–I

air

0.08

0.06

Current (A)

I

H

2

–I

air

(A)

0.04

0.02

0.00

0 2 4

Voltage (V)

6 8 10

0.000

0.002

0.004

0.006

0.008

0.010

Reference diode

@ 25°C

Air

1% H

2

I

H

2

–I

air

FIGURE 3.13  Absolute and differential current of HEMT diodes measured at 25°C.

108 Semiconduc ...