The Preparation Of The Laterally Inhomogeneous Nanocrystalline Silicon (nc-si) Thin Film Of Cuprous Oxide Films And Its Characteristics

The thesis includes two parts. In the first part, we have studied the transversal thermovoltaic effect of the nc-Si thin film with different crystallization degree. In the second part, we have prepared and studied the cuprous oxide (CU2O) film photovoltaic materials.Two transversal contacted nanocrystalline Si (nc-Si):amorphous Si (a-Si) films with different crystallization degree has been prepared on a quartz substrate by crystallizing a 200 nm thick amorphous Si (a-Si) film using two different thick Al films (50nm and l00nm) deposited on it, and annealing at 600℃for 45 min, in N2. The structural properties of the prepared films have been studied by X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM) and TEM. The thermovoltaic effects of the prepared films have been studied by self-made measurement device. We have used two simple chemical methods to prepare Cu2O film. The first one is that copper plate was put into boiling CuSO4 solution which is used to prepare Cu2O film; The second one is that copper plate was put into CUSO4 solution for 12h under room temperature. The structural properties of the prepared films have been studied by XRD, atomic force microscope (AFM), SEM. The optical properties of the prepared films have been studied by ultraviolet-visible infrared spectrophotometer (UV-VIS) and PL. In this thesis, we obtained the following conclusions:1. XRD measurements indicate that the average size of nc-Si film induced by Al film is 25nm in region A and 15nm in region B.2. Raman spectra research proves that the nanocrystalline silicon exist in annealing sample. Through Gauss fitting, we can estimate the crystallization rate is 56% and 23% in region A and B, respectively. The research results indicate that both the crystalline volume fraction and size of crystalline grain increase with the thickness of A1 film increase, which is consistent with XRD measurements.3. TEM measurements indicate that during annealing process layer exchange has happened between A1 and a-Si layers.4. Thermovoltaic effect tests proves that there is a transversal thermovoltaic effect between the two nc-Si films, which is uniformly heated in the absence of external temperature gradients. The open circuit voltage and short circuit current is 1.2mV/40 nA at 273K,25mV/1.171μA at 373K.5.The best condition of experiment is:Boiling copper plates in CUSO4 solution for 1h, the thickness of film can be 1.5μm, and Cu2O grain size can reach the micron-grade;6. The Optical properties of the Cu2O film were studied by ultraviolet-visible infrared spectrophotometer (UV-VIS) and the optical band-gap energies of the films prepared using two different methods were determined to be 1.91eV and 1.88eV, respectively.7. The observed PL band centered at 510nm and 540nm are all attributed to the optical bandgap of the Cu2O.