CORRELATION BETWEEN STRUCTURAL, OPTICAL, AND ELECTRICAL-PROPERTIES OF GAAS GROWN ON (001) SI

In this study transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), and electrochemical capacitance-voltage measurements were used to characterize undoped GaAs films, grown by organometallic vapor phase epitaxy on (001) Si substrates. TEM studies indicated that the high defect density (threading dislocations and microtwins), present close to the interfacial region, drops rapidly with distance away from the interface. PL studies also indicated an increase in PL intensity and significant narrowing of the full-width at half-maximum of the excitonic transition with an increase in layer thickness, indicating an improvement in the optical quality of the epilayers. Electrochemical capacitance-voltage measurements indicated a uniform carrier concentration (low to mid 10(15) cm-3 range), which is among the lowest yet to be reported for GaAs/Si grown by organometallic vapor phase epitaxy.