A New GaAs Metal-Semiconductor-Metal Photodetector Based on Hybrid Plasmonic Structure to Improve the Optical and Electrical Responses

In this article, a new hybrid plasmonic based metal-semiconductor-metal photodetector (MSM-PD) is proposed. A subwavelength slit, the metal nanoscale gratings, and the metal pads which are extended into the absorption layer are used in a basic hybrid plasmonic structure to enhance the absorption coefficient. The finite-difference time-domain (FDTD) method is used to simulate the new structure. The absorption coefficient of the hybrid plasmonic MSM-PD becomes 42 times greater than that of the conventional plasmonic MSM-PD made of only subwavelength slit, which is known as the reference structure. This result is equivalently about 1.5 times greater than that of a recently reported structure. It is also demonstrated that the quantum efficiency of the proposed structure is 10 times more, if compared with the reference one. Moreover, considering the incident light modulation frequency, the frequency response of the hybrid plasmonic MSM-PD is improved, where the cutoff frequency is increased 22 times greater than that of the reference MSM-PD.