We investigate the optical properties of CdTe quantum dots (QDs) in a Cd0.3Zn0.7Te quantum well (QW) grown on GaAs (100) substrates. Carrier dynamics of CdTe/ZnTe QDs and quantum dots-in-a-well (DWELL) structure is studied using time-resolved photoluminescence (PL) measurements, which show the longer exciton lifetime of the DWELL structure. The activation energy of the electrons confined in the DWELL structure, as obtained from the temperature-dependent PL spectra, was also higher than that of electrons confined in the CdTe/ZnTe QDs. This behavior is attributed to the better capture of carriers into QDs within the surrounding QW.

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We investigated the effective channel length (L eff. ) of a-IGZO single layer and bi-layer. In the I-V curve, the drain-induced barrier lowering (DIBL) phenomenon appeared to be severe in the single layer, while it was relatively improved in the Bi layer. Based on this, we have determined the effective channel length through transmission line method (TLM) and confirmed that the effective channel length of the Bi layer is longer. The threshold voltage variation for each design length from 3.5 to 8.5 μm was also smaller in the Bi-layer. The results of XPS analysis show that this was due to the oxygen decomposition by Ti. In the Bi-layer with Ga-rich top layer, the high conduction region due to the oxygen decomposition phenomenon was reduced.