Interplay Between Strain and Thickness on the Effective Carrier Lifetime of Buffer-Mediated Epitaxial Germanium Probed by the Photoconductance Decay Technique

被引：2

作者：

Bhattacharya, Shuvodip ^{[1
]}

Johnston, Steven W. W. ^{[2
]}

Datta, Suman ^{[3
,4
]}

Hudait, Mantu K. K. ^{[1
]}

机构：

[1] Virginia Tech, Bradley Dept Elect & Comp Engn, Adv Devices & Sustainable Energy Lab ADSEL, Blacksburg, VA 24061 USA

[2] Natl Renewable Energy Lab, Golden, CO 80401 USA

[3] Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA

[4] Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA

来源：

ACS APPLIED ELECTRONIC MATERIALS | 2023年 / 5卷 / 06期

关键词：

germanium; carrier lifetime; tensile strain; molecular beam epitaxy; x-ray diffraction; photoconductance; bulk lifetime; surface recombinationvelocity; SURFACE RECOMBINATION; BULK LIFETIME; SILICON; GE; SEMICONDUCTORS; PERFORMANCE; MICROWAVE; FUTURE;

D O I：

10.1021/acsaelm.3c00256

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

We report contactless effective minority carrier lifetimeof epitaxiallygrown unstrained and in-plane biaxially tensile-strained(001) germanium (epsilon-Ge) epilayers measured using microwave-reflectancephotoconductance decay measurements. Strained Ge epilayers were grownusing In x Ga1-x As linearly graded buffers on (001) GaAs substrates. Usinghomogeneous excitation of unstrained Ge epilayers, thickness-dependentseparation of minority carrier lifetime components under low injectionconditions yielded a bulk lifetime of 114 +/- 2 ns and low surfacerecombination velocity of 21.3 +/- 0.04 cm/s. More notably, aneffective minority carrier lifetime of >100 ns obtained from sub-50nm 1.6% tensile-strained Ge epilayers showed no degradation relativeto the unstrained counterpart. Detailed material characterizationusing X-ray diffractometry revealed successful strain transfer of0.61 and 0.89% to the Ge epilayers via In x Ga1-x As metamorphic buffers andconfirms pseudomorphic growth. Lattice coherence observed at the epsilon-Geepilayer and In x Ga1-x As buffer heterointerfaces via transmission electronmicroscopy substantiates the prime material quality achieved. Therelatively high carrier lifetimes achieved are an indicator of excellentmaterial quality and provide a path forward to realize low-thresholdGe laser sources.

引用

页码：3190 / 3197

页数：8