高倍增低暗电流AlInAsSb四元数字合金雪崩光电二极管

High gain and low dark current AlInAsSb avalanche photodiodes grown by quaternary digital alloys

用分子束外延系统(MBE)生长高质量GaSb基AlInAsSb四元数字合金制作雪崩光电二极管(APD)。为了克服随机体材料生长方式发生的偏析现象,采用迁移增强的数字合金生长方式,其快门顺序为AlSb,AlAs,AlSb,Sb,In,InAs,In,Sb。其高分辨率X射线衍射(HRXRD)曲线显示出尖锐的卫星峰,并显示出几乎完美的晶格匹配,其原子力显微镜(AFM)图像上也可以观察到光滑的表面形貌。使用优化的数字合金生长方式,制备了分离吸收、渐变、电荷和倍增(SAGCM)型的AlInAsSb数字合金APD。在室温下,器件在95%击穿时,暗电流密度为0.95 mA/cm2,击穿前最大稳定增益高达~100,其器件的高性能显示出光电领域进一步发展的潜力。

avalanche photodiodes(APD)have been fabricated using high quality GaSb-based AlInAsSb quaternary digital alloy grown by molecular beam epitaxy(MBE).To overcome the tendency towards phase segregation of random alloy,a digital alloy technique with migration-enhanced epitaxy growth method was employed,using a shutter sequence of AlSb,AlAs,AlSb,Sb,In,InAs,In,Sb.The HRXRD curve shows sharp satellite peaks and almost perfect lattice matching.The smooth surface morphology can also be observed on the AFM image.Using optimized digital alloy,AlInAsSb separate absorption,grading,charge,and multiplication(SAGCM)APD was grown and fabricated.At room temperature,the device showed high performance with low dark current density of 0.95 mA/cm2 at 95%breakdown and maximum stable gain before breakdown as high as 100,showing the potential for further applications of optoelectronics.