http://dspace-roma3.caspur.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. 2013-05-18T11:32:36Z http://hdl.handle.net/2307/317 <Title>Terahertz intersubband absorption and conduction band alignment inn-type Si/SiGe multiple quantum wells</Title> <Authors>Ciasca, Gabriele; De Seta, Monica; Capellini, Giovanni; Evangelisti, Florestano; Ortolani, Michele; Virgilio, Michele; Grosso, Giuseppe; Nucara, Alessandro; Calvani, Paolo</Authors> <Issue Date>2009</Issue Date> <Is part of>Phisical review B</Is part of> <Volume>79</Volume> <Pages>085302</Pages> <Abstract>Absorption due to conduction intersubband transitions is studied inn-type s-Si/SiGe multiquantum wells (MQW) of different well widths andbarrier composition grown by UHV-chemical vapor deposition (CVD). Themeasured intersubband transition energies are compared with thetheoretical results of a tight-binding model which provides theelectronic band structure of the complete MQW system throughout thewhole Brillouin zone. Our findings demonstrate both the high quality ofthe CVD grown MQWs and the effectiveness of the adopted tight-bindingmodel in describing band profiles and electronic structures of SiGemultilayer systems. In particular we have evaluated the conduction bandoffsets in the investigated structures.</Abstract> 2008-12-31T23:00:00Z http://hdl.handle.net/2307/314 <Title>Conduction band intersubband transitions in Ge/SiGe quantum wells</Title> <Authors>De Seta, Monica; Capellini, Giovanni; Busby, Yan; Evangelisti, Florestano; Ortolani, Michele; Virgilio, Michele; Grosso, Giuseppe; Pizzi, Giovanni; Nucara, Alessandro; Lupi, Stefano</Authors> <Issue Date>2009-08</Issue Date> <Is part of>Applied Physics Letters</Is part of> <Volume>95</Volume> <Pages>051918-051918-3</Pages> <Abstract>In this letter we present the experimental evidence of intersubbandabsorption in the conduction band of compressively strained germaniumquantum wells bounded by Ge-rich SiGe barriers. The measured absorptionenergies are in the terahertz range and are interpreted by means oftight binding calculations which include self-consistent band-bendingand depolarization effects. From the comparison of experimental andnumerical results a conduction band offset along the L line of about120 meV has been estimated for the studied heterostructures.</Abstract> 2009-07-31T22:00:00Z