| Summary: | 碩士 === 國立成功大學 === 電機工程學系 === 85 === Atomic layer epitaxy (ALE) growth and characterization of ZnSSe on n-type (100) Si substrates are investigated for the first time by a low pressure horizontal MOCVD system using DMZn, H2S and H2Se as the reactants. Energy Dispersive Spectrometer attacehd on Scanning Electron Microscopy (SEMEDS), X-ray Diffraction (SIMS) ere used to determine the elemental composition and depth profile. Electrical and optical properties of the ZnSSe epilayers are characterized by current-voltage (I-V) measurements, Hall measurements and photoluminescence (PL).
Undoped ZnSSe epilayers were grown at the growth temperature of 175℃ and pressure of 30 torr. The vapor-solid distribution relationship for the group VI elements is experimentally obtained. The layer lattice-matched to the Si substrate at a sulfur content about 93％ shows a better surface morphology and a narrower FWHM of XRD. From PL spectra, the ZnSSe energy gaps were deduced and a stronger near band edge was exhibited at the epilayer of ZnS0.93 Se0.07.
The highest Hall mobility of the undoped ZnS0.93 Se0.07 is 347 cm2/v-sec. The Schottky diode has an excellent electrical properties at room temperature such as low leakage current, 45 nA at 20 V reverse voltage, high breakdown voltage over 40 V, and with low cut-in voltages of 0.68V. These results suggest that the Si substrates may be available for growing sufficiently high-quality by ALE.
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