采用分子柬外延(MBE)技术,在GaSb衬底上生长了pin结构InAs(8ML)/GaSb(8ML)超晶格材料,响应光谱显示截止波长在5μm附近。通过腐蚀、光刻、溅射等工艺,制备了pin结构中波红外光电二极管。采用(NH4)。S+ZnS双层硫化对二极管表面进行钝化,(NH4)2S硫化后的二极管表面漏电流密度降低一个数量级,零偏阻抗风增大几十倍,达到10^3欧姆。采用ZnS钝化后,漏电进一步减小,黑体探测率达到1×10^9,cmHz^1/2W^-1。在空气中放置一个月后再测试,信号和探测率几乎没有变化。
InAs(8 ML)/GaSb(8 ML) superlattice with p-i-n structure was grown on GaSb substrates by molecular beam epitaxy. The absorption cutoff wavelength of this superlattice was 5 p.m by transmition spectra. The mid-wavelength infrared photodiode with different area mesa was fabricated through standard photolithography, wet chemical etching and sputtered metal contacts. The passivation was finished by the (NH4)2S solution treatment and ZnS layer. After the treatment, the surface leakage currents density decreased one order of magnitude and the R0 increased up to 103 ohms. The blackbody detectivity D* was 1×10^9,cmHz^1/2W^-1at 77 K. The property of the photodiode appeared no degradation after exposured in air for one month.