GAS MONITORING DEVICE, COMBUSTION STATE MONITORING DEVICE, SECULAR CHANGE MONITORING DEVICE, AND IMPURITY CONCENTRATION MONITORING DEVICE
First Claim
1. A gas monitoring device for monitoring a gas using light in the near-infrared region with a wavelength range of 3 μ
- m or less, the gas monitoring device comprising;
a light-receiving element that receives light in the near-infrared region,wherein the light-receiving element includes an absorption layer formed on an InP substrate and having a multiquantum well structure,the absorption layer has a bandgap wavelength of 1.8 μ
m or more and 3 μ
m or less; and
a diffusion concentration distribution control layer is disposed on a surface side of the absorption layer, the surface side being opposite the InP substrate,the diffusion concentration distribution control layer has a bandgap smaller than that of InP,in the light-receiving element, a pn-junction is formed by selectively diffusing an impurity element through the diffusion concentration distribution control layer so as to reach the absorption layer,the concentration of the impurity element in the absorption layer is 5×
1016/cm3 or less, andthe light-receiving element receives light from the gas, the light having at least one wavelength of 3 μ
m or less, to detect a gas component and the like contained in the gas.
1 Assignment
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Accused Products
Abstract
[Object] To provide a gas monitoring device etc. with which gas monitoring can be preformed at high sensitivity by using an InP-based photodiode in which a dark current is reduced without a cooling mechanism and the sensitivity is extended to a wavelength of 1.8 μm or more.
[Solution] An absorption layer 3 has a multiquantum well structure composed of group III-V semiconductors, a pn-junction 15 is formed by selectively diffusion of an impurity element in the absorption layer, and the concentration of the impurity element in the absorption layer is 5×1016/cm3 or less. The gas monitoring device detects a gas component and the like contained in a gas by receiving light having at least one wavelength of 3 μm or less.
13 Citations
20 Claims
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1. A gas monitoring device for monitoring a gas using light in the near-infrared region with a wavelength range of 3 μ
- m or less, the gas monitoring device comprising;
a light-receiving element that receives light in the near-infrared region, wherein the light-receiving element includes an absorption layer formed on an InP substrate and having a multiquantum well structure, the absorption layer has a bandgap wavelength of 1.8 μ
m or more and 3 μ
m or less; anda diffusion concentration distribution control layer is disposed on a surface side of the absorption layer, the surface side being opposite the InP substrate, the diffusion concentration distribution control layer has a bandgap smaller than that of InP, in the light-receiving element, a pn-junction is formed by selectively diffusing an impurity element through the diffusion concentration distribution control layer so as to reach the absorption layer, the concentration of the impurity element in the absorption layer is 5×
1016/cm3 or less, andthe light-receiving element receives light from the gas, the light having at least one wavelength of 3 μ
m or less, to detect a gas component and the like contained in the gas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
- m or less, the gas monitoring device comprising;
Specification