ZnSe-ZnS超晶格的通光蚀孔及列阵研究

STUDY OF ETCHING HOLE AND ARRAY OF ZnSe-ZnS SIS

用MOCVD方法在GaAs衬底上生长ZnSe-ZnS超晶格.用化学腐蚀方法在GaAs衬底上开一个通光窗口,使该窗口上仅剩有1～1.8μm厚的生长层.室温下测量了蚀孔后由于化学腐蚀造成生长层表面差异的ZnSe-ZnS超晶格的吸收光谱.研究了带有生长过渡层和无过渡层的超晶格质量对其吸收光谱性能的影响.发现过渡层的存在保护了超晶格激子吸收性能.在此基础上首次采用新工艺在3×3mm^2面积上把GaAs衬底金部腐蚀掉,剩下均匀、光滑的ZnSe-ZnS超晶格层,在其上做出了300×300μm^2的列阵,为在ZnSe-ZnS超晶格上实现光学双稳的集成化提供了必要条件.

ZnSe-ZnS superlattices(SLS) are grown by MOCVD on (100) GaAs substrstes, following the deposition of a 1μm-thick ZnS buffer layer. Each sample is composed of 50 ZnSe wells of thicknesses Lw= 8nm and 50 ZnS barries of thicknesses Lb= 8nm, respectively. The samples are stuck on clear glr.ss so that the GaAs substrate material is exposed. The GaAs substrate is mechanically lapped to a thickness of 200-300μm and then etched a light window with a selective chemical etch.Three light windows, on which the thicknesses of SLS and ZnS are 0.8 and 1μm,respectively, are obtained on the same sample after chemical etching hole and their absorption spectra are measured at room temperature. It is found that the excitonic absorption properties of three holes are the same although the qualities of surface of grown layer near to GaAs are not same because of effect of chemical etching on its growth layer. The one of three light windows is cleaved and the etching depth is measured by using SEM. It is found that the existence of ZnS buffer layer protects the excitonic properties of SLS layer because the etched depth is less than thickness of ZnS buffer layer.The light window area of 3×3mm2 with grown layer of l.8μm in thick have been obtained by anodization methode for the first time. Microscope observation (×120) shows the light window surface near to GaAs is very smooth. The 300×300μm2 multiple arraies on the ZnSe-ZnS SLS of 3×3mm2 have been carried out recently. This result shows it is possible to obtain the integration of optical switching and optical computing devieces in ZnSe-ZnS SLS.