| Summary: | 碩士 === 國立交通大學 === 光電工程所 === 91 === We have successfully fabricated GaSe thin films on different substrates. From (004) peak position and FWHM of XRD, we observe that quality of GaSe/Si(111) series is the best compared to GaSe/GaN and GaSe/Sapphire at the same thickness due to small lattice mismatch. We also find that c-axis length of GaSe thin films were stretched larger at initial stage of deposition and the increasing amount (c) are GaSe/Sapphire, GaSe/GaN and GaSe/Si(111) in order. The crystalline of GaSe thin films can also be evaluated by Raman Al’ mode which vibrates along c-axis and E’(LO) mode which vibrates perpendicular to the c-axis of GaSe. From the analysis of FWHM of A1’mode, the tendency is identical compared with XRD result. In addition, we also find that the A1’mode shift to lower frequency due to the c-axis length stretched larger which were presumed in accordance with ref[23]. From AFM analysis, the growth mode might be SK mode. The result is different from GaSe deposited by MBE system (layer by layer mode) which belong to VdWE. After the analysis of XRD, Raman spectra and AFM, we find that the behavior is unlike VdWE or quai-VdWE. Hence the lattice mismatch is an important parameter we must consider when we deposit GaSe thin films by pulsed laser deposition.
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