Thermally Treated Ge Crystallites Embedded inside PS with Si Capping Layer for Potential Photonics Application

In this work we use a very low cost and conventional technique to prepare Ge nano/microstructures by means of filling the material inside porous silicon (PS) using thermal evaporator. PS was prepared by anodization of Si wafer in ethanoic hydrofluoric acid (HF). The Ge layer was then deposited onto the PS by thermal evaporation. A Si capping layer was then deposited on to the Ge layer by thermal evaporator. Subsequent annealing at 650 degrees C and 750 degrees C for 30 mins were done to drive in the Ge inside PS structure. The process was completed by inter-digitated Ni metal deposition using thermal evaporator to form metal-semiconductor-metal (MSM) structure. SEM of the structures showed uniform square-pores with estimated size of 100nm to 500nm and EDX suggests the presence of Ge inside the pores structure. Raman spectrum showed that a good crystalline structure of the Ge can be produced inside the silicon pores. XRD revealed Ge tetragonal structures by (201), (113) and (204) reflections. Finally current-voltage (I-V) measurement of the Si/Ge/PS MSM photodetector was carried out to show potential application in photonics.