| 摘要 |
The photodetector of infrared radiation comprises a photo-absorption layer (13) of multiple quantum well (MQW) structure formed on a semiconductor substrate (11), a diffraction grating pattern (14b) containing curved elements distributed with unique steps, first and second semiconductor layers (12,14) for the transmission of radiation, and a reflecting film (16) covering the diffraction grating pattern and having the role of cathode. The photodetector of infrared radiation comprises a photo-absorption layer (13) of multiple quantum well (MQW) structure formed on a semiconductor substrate (11), a diffraction grating pattern (14b) containing curved elements distributed with unique steps, first and second semiconductor layers (12,14) for the transmission of radiation, and a reflecting film (16) covering the diffraction grating pattern and having the role of cathode. The diffraction grating diffracts the radiation passed through the semiconductor substrate and the photo-absorption layer, and produces a distribution of intensity which is high in the direction practically parallel to the photo-absorption layer, and low at angles within a cone of about 18 degrees with respect to a perpendicular to the same layer. The curved elements of the diffraction grating are of elliptic curves form. The height of the diffraction grating pattern is not greater than half the absorption wavelength. The diffraction grating is formed so that the area of elements is equal to the area where the elements are not formed. The structure of the photo-absorption layer (13) is that of multiple quantum wells, quantum line or quantum box. The multiple quantum well layer is formed by layers of composite semiconductors, crossing and alternating layers of gallium arsenide (GaAs) and aluminum gallium arsenide (AlGaAs). The procedure for manufacture includes the stage of the formation of the photo-absorption layer (13) on the semiconductor substrate (11), the formation of the transmission layer (14), the formation of mask (15), the formation of the diffraction grating pattern (14b) by printing, and the lifting of mask. |
