Strained piezoelectric [111] multiple quantum wells: clamped or free?

✍ Scribed by X.R. Huang; D.S. McCallum; D.R. Harken; A.N. Cartwright; Arthur L. Smirl; A. Sacedón; J.L. Sánchez-Rojas; E. Calleja; E. Muñoz

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 144 KB
• Volume: 15
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1994.1034

✦ Synopsis

We illustrate a procedure whereby the nonlinear optical response can be used to deternine the strain distribution in properly engineered InGaAs/GaAs multiple quantum well (MQW) structures with piezoelectric fields along the growth direction. We do this by fabricating two (\mathrm{p}-\mathrm{i}(\mathrm{MQW})-\mathrm{n}) samples which are designed such that, if the materials are mechanically clamped, the quantum well exciton of one will shift to the blue upon optical excitation, whereas the quantum well exciton of the other will shift to the red. However, if the materials are mechanically frec, the quantum well excitons of both samples will shift to the red. We illustrate the technique by determining that InGaAs/GaAs MQWs grown on [111]-oriented GaAs substrates are (as expected) mechanically clamped. That is, that we observe an excitonic blue shift in one sample, and a red shift in the other.