Characterization of AlInAsSb and AlGaInAsSb MBE-grown Digital Alloys
Characterization of AlInAsSb and AlGaInAsSb MBE-grown Digital Alloys
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AlInAsSb 和 AlGaInAsSb MBE 生长的数字合金的表征
DOI：
10.1557/proc-744-m7.2
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
L. Lester
中科院分区：
文献类型：
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作者：
L. Vaughn;L. Ralph;Huifang Xu;Y. Jiang;L. Lester
作为为数不多的可用于3.3 ~ 4.2微米中红外多量子阱激光器的I型波段偏移、锑基材料体系之一，AlInAsSb合金已被用作InAsSb阱的屏障。在此之前，Al x In (1-x) As y Sb （1-y）季元合金已经通过MBE作为随机合金生长到铝分数，在GaSb衬底上x = 0.10，在InAs衬底上x = 0.15。随着铝含量的增加，四元薄膜的无序合金生长虽然对器件有利，但受混相间隙的限制。我们已经使用数字合金技术来生长稳定的、单相的、GaSb晶格匹配的、光学光滑的四元合金，铝分数为0.05到0.5，完全进入混相间隙。DCXRD结果表明，0阶合金峰的FWHM是高结晶GaSb衬底的1.5 ~ 2倍，并具有与总薄膜厚度和数字合金周期相对应的明确的厚度条纹。TEM图像显示，合金具有超薄超晶格结构，具有光滑的界面、很小的应变和受数字合金技术限制的原子有序度。光致发光测量被用来拟合一个模型，从已知的合金成分预测带隙。理论研究预测，第五元素镓的加入可能通过对子带结构的影响来帮助抑制俄歇复合。因此，将镓添加到四元合金中，生成与GaSb匹配的四元合金晶格。这些AlGaInAsSb合金的DCXRD和TEM结果与第四纪相似。这些四元合金在整个组成范围内稳定的单相生长，有望改善中红外激光器的工作特性。
As one of the few Type I band offset, antimony-based material systems available for 3.3 to 4.2 micron mid-infrared multiple quantum well lasers, AlInAsSb alloys have been used as barriers with InAsSb wells. Previously, Al x In (1-x) As y Sb (1-y) quaternary alloys have been grown by MBE as random alloys up to an aluminum fraction, x = 0.10 on GaSb substrates and x = 0.15 on InAs substrates. Random alloy growth of quaternary films with increased aluminum content, although beneficial to the devices, is limited by a miscibility gap. We have used a digital alloy technique to grow stable, single phase, GaSb lattice-matched, optically smooth quaternary alloys for aluminum fractions of 0.05 to 0.5, well into the miscibility gap. DCXRD results show FWHM of 0 th order alloy peaks are within 1.5 to 2 times that of the highly crystalline GaSb substrates and have well defined thickness fringes corresponding to the total film thickness and the digital alloy period. TEM images show very well ordered alloys with characteristic ultrathin superlattice structure having smooth interfaces, very little strain and atomic ordering limited to that imposed by the digital alloy technique. Photoluminescence measurements are used to fit a model for bandgap prediction from known alloy compositions. Theoretical studies have predicted that the addition of a fifth element, gallium, may help suppress Auger recombination through its effects on the subband structure. So, gallium is added to the quaternary to produce a quinternary alloy lattice-matched to GaSb. These AlGaInAsSb alloys have DCXRD and TEM results similar to the quaternary. The stable, single-phase growth of these quinternary alloys across the composition range is promising for improving the operating characteristics of mid-IR lasers.