Electronic structure of semiconductor interface is very interesting. However, conventional surface diagnostics have limited penetration depth and are in some case destructive. In the past, no specific optical spectroscopies can be effectively employed to study the electronic structure of semiconductor interface. Recently, sum frequency and second harmonic generation ( SHG ) spectroscopy is shown to be able to obtain the information of the electronic structure of semiconductor interface. Reflectance difference spectroscopy ( RDS ) is also a sensitive technique to study the electronic structure of semiconductor surface and interface'. Optical properties of ZnSe/GaAs interface are studied, in details, by reflectance difference spectroscopy. It is shown that two resonance lines, observed at...[ Read more ]

Electronic structure of semiconductor interface is very interesting. However, conventional surface diagnostics have limited penetration depth and are in some case destructive. In the past, no specific optical spectroscopies can be effectively employed to study the electronic structure of semiconductor interface. Recently, sum frequency and second harmonic generation ( SHG ) spectroscopy is shown to be able to obtain the information of the electronic structure of semiconductor interface. Reflectance difference spectroscopy ( RDS ) is also a sensitive technique to study the electronic structure of semiconductor surface and interface'. Optical properties of ZnSe/GaAs interface are studied, in details, by reflectance difference spectroscopy. It is shown that two resonance lines, observed at 2.7 eV and 3.1 eV, are mainly due to the optic anisotropy within the interface plane. The optic anisotropy could be caused by an interface electric field due to interdiffusion of Zn and Ga atoms during MBE growth. However, no Franz Keldysh oscillation is observed by the measurement of photoreflectance before and after annealing experiment. As a result, it cannot be concluded that an interface electric field exists in our samples. It is also suggested that the anisotropy may be the intrinsic properties of ZnSe/GaAs interface caused by the " memory" of the frost few ZnSe monolayers of reconstruction structure of the substrate surface prior to growth. Further study of interfaces with well controlled initial growth conditions should reveal more about the nature of information.