Direct gap related optical transitions in Ge/SiGe quantum wells

✍ Scribed by M. Bonfanti; E. Grilli; M. Guzzi; D. Chrastina; G. Isella; H. von Känel; H. Sigg

• Book ID: 104085543
• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 334 KB
• Volume: 41
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/j.physe.2008.08.052

✦ Synopsis

An experimental study of the direct-gap related optical transitions in strain-compensated Ge/Si 0.15 Ge 0.85 multiple quantum wells (MQWs) is presented. These structures are of particular interest due to the proximity of G-type and L-type conduction band states and due to their type I band alignment. The samples were grown by low-energy plasma-enhanced CVD and consist of Ge MQWs with a large numbers of periods and good morphological quality grown onto thick graded Si 1Àx Ge x buffer layers. The transmission spectra, which shows clear evidence of excitonic transitions, are studied as a function of temperature in the 5-300 K range. Preliminary results of photocurrent measurements performed on the same structures using metal-semiconductor-metal contact are discussed.