Effect of dimensional parameters on the current of MSM photodetector
In this work, we present the influence of dimensional parameters on dark current and photocurrent of the metalsemiconductormetal photodetector (MSM). MSM photodetectors of different sizes have been fabricated on GaAs (NID). The active area of MSM samples varies between 11?m2 and 1010?m2 with equal electrodes spacing and finger widths (l=D) varying between 0.2 and 1?m. The I(V) characterization in inverse and direct polarization in darkness shows good symmetry of curves, which shows the good performance of components and successful fulfillment of the Schottky contacts. The application of laser fiber of incident light power of 16mW at wavelength of 850nm for the illumination of the MSM photodetectors showed the evolution of the photocurrent ranging from 0.75 to 1.81mA, respectively, for 1 to 0.2?m electrodes spacing at 3V and active area S=33?m2. We showed also that variation ranging from 0.45 to 2.5mA, respectively, for S=11?m2 to S=1010?m2 at 3V and 0.3?m electrodes spacing. The resistance of MSM photodetectors obtained evolved proportionally to the electrodes spacing (0.87k? for D=0.2?m and 2.27k? for D=1?m with S=33?m2) and inversely proportional to the surface area (2.02k? for S=11?m2, and 0.56k? for S=1010?m2 with 0.3?m inter electrodes spacing).
photodetectors schottky contact metalsemiconductormetal (msm) gallium arsenide (gaas)