摘要： The photon trapping structure helps to enhance the quantum efficiency (QE) in ultra-thin metal-semiconductor-metal (MSM) photodetectors so that they can achieve high speed while maintaining less than 1 micron thickness. The study shows that the short pulse response is shorter if the device is thinner. For the thin layer of Si with thickness 250nm the pulse response is 2ps, while for 400nm and 700nm the pulse responses are 3ps and 5ps, respectively. The QE for the thin layer of Si with nano-holes is higher than the flat Si with the same thickness. The QE for 250nm Si with nano-holes is 60% at 850nm wavelength, while for flat Si with the same thickness is 20%. The QE for 400nm Si with nano-holes is 80% at 850nm wavelength, while for flat Si with the same thickness is 40%. The QE for 700nm Si with nano-holes is 90% at 850nm wavelength, while for flat Si with the same thickness is 60%. The QE for 1500nm Si with nano-holes is 95% at 850nm wavelength, while for flat Si with the same thickness is 80%. The QE for the thin layer of Si with nano-holes is higher than the flat Si with the same thickness. The QE for 250nm Si with nano-holes is 60% at 850nm wavelength, while for flat Si with the same thickness is 20%. The QE for 400nm Si with nano-holes is 80% at 850nm wavelength, while for flat Si with the same thickness is 40%. The QE for 700nm Si with nano-holes is 90% at 850nm wavelength, while for flat Si with the same thickness is 60%. The QE for 1500nm Si with nano-holes is 95% at 850nm wavelength, while for flat Si with the same thickness is 80%.