تحسين داخل منصورأ.م.د. سامر مهدي عبد المحسن / أ.د امين حبيب السيد جاسم2025-02-202025-02-202017-07-20https://dspace.utq.edu.iq/handle/123456789/826The increasing world crises of clean energy supply become global issues in recent years. So, it is of importance to develop solutions for these problems. Solar energy is one of the promising renewable energy sources. It has a great potential since that the surface of the earth is receiving enough amount of energy for suppling global demand over the year. One of the main shortcomings in solar cell devices is the low quantum efficiency. Due to its superior characteristics, QD nanocrystals are proposed for high efficiency solar cells. This work devotes to study quantum efficiency of CdS/ZnO, CdSe/ZnO II-VI and TiO2/MgZnO IV-VI QD solar cells. These structures are covers the range of 1.84 3.2  eV from the emission spectrum. In chapter two; assuming the quantum disk shape of the QDs, their band structures were calculated for different QD heights ( ) h and radii ( )  . The QD sizes studied are; h nm  2  12,13,14nm and h nm 1, 3 ,  13nm Then, assuming QD layers are n- and p- doped for CdS/ZnO, CdSe/ZnO while TiO2 QDs was n- doped and MgZnO barrier was p- doped. Their absorption spectra were calculated in the same chapter. Mainly, there are two absorption peaks. Reducing QD height degrades the peak in considerable amount and reduces the width of the spectrumtext::thesis::master thesis