Single crystal Silicon-Germanium multi-quantum well layers were epitaxially grown on silicon substrates. Very high quality films were achieved with high level of control utilizing recently developed MHAH epitaxial technique. MHAH growth technique facilitates the monolithic integration of photonic functionality such as modulators and photodetectors with low-cost silicon VLSI technology. Mesa structured p-i-n photodetectors were fabricated with low reverse leakage currents of ~10 mA/cm 2 and responsivity values exceeding 0.1 A/W. Moreover, the spectral responsivity of fabricated detectors can be tuned by applied voltage. for optical communications," Appl. Phys. Lett. 81(4), 586-588 (2002 ©2012 Optical Society of America

Cataloged from PDF version of article.The temperature dependence of current is\ud investigated experimentally for silicon–germanium (Si-Ge)\ud multi-quantum-well p-i-n devices on Si substrates as uncooled\ud bolometer active layers. Temperature coefficient of resistance\ud values as high as −5.8%/K are recorded. This value is\ud considerably higher than that of even commercial bolometer\ud materials in addition to being well above the previous efforts\ud based on CMOS compatible materials

ÖZET yüzyılda dünyanın ulaştığı teknolojik seviye, yaklaşma iniş sistemleri konusunda yeni bir çağ başlatmıştır. Tüm dünyada sivil ve askeri hava araçlarının iniş ve kalkışlarında halen kullanılan Hassas Yaklaşma Radarı ve DERGİSİ TEMMUZ 2014 CİLT 7 SAYI 2 (15-26)

Silicon-Germanium quantum wells were grown in p-i-n layers using a recently developed epitaxial technique. Nanostructural characterization (TEM, XPS, photoluminescence) indicates low-dislocation density, high quality films. Solar cells made of these layers have low leakage current.Current state-of-the-art near infrared photodetectors are based on InGaAs [1], due to WKH PDWHULDO ¶V (i) ease of integration with InGaAsP lasers for optical communication systems [2], (ii) high degree of tunability of the direct band gap energy and absorption [3] and (iii) low dark current using lattice matched wide bandgap materials [4]. The mature Silicon CMOS technology provides a lower cost platform while optoelectronics offers high performance and increased functionality. By integrating the two, one can meet the stringent market conditions of performance and functionality. Despite its performance advantage, current III-V technology suffers from (i) significant high cost of integration with Si CMOS [5], (ii) and high raw material costs [6,7]. Bulk Silicon is not suitable for photodetection in the telecommunication bands, since it cannot absorb strongly in the near infrared owing to its wide bulk band gap HQHUJ\ a H9 )RU WRGD\ ¶V RSWRHOHFWURQLF GHYLFH DSSOLFDWLRQV *HUPDQLXP holds great promise with an absorption spectrum (E g(direct) = 0.8 eV, E g(indirect) = 0.66 eV) spanning the telecommunication wavelengths at which Si is transparent. By growing Ge on Si, it is also possible to integrate CMOS circuitry with optoelectronic components on single chip, which promises higher density and extended functionality [8].Integration of Ge-based optoelectronic devices with Silicon demands high quality Ge layer growth. Ge growth on Si, however, is encumbered by the large lattice mismatch (4.2%) [6,7]. Nayfeh and coworkers recently introduced multiple hydrogen annealing heteroepitaxy (MHAH), technique achieving low defect density Ge layers on Si [8][9][10]. Here, we report the growth, optical and nanostructural characterization and device characterization of the MHAH-grown high quality thin Ge multi quantum well (MQW) films and the solar-cell characterization for devices made of these thin film MQW. The layers are doped in-situ forming an n-i-p structure with 10 pairs of quantum wells. MQWs provide (i) the ability to tune the material absorption by changing the bilayer thickness of each quantum well-barrier for operation at different wavelengths and (ii) the ability to exploit the quantum confined Stark effect (QCSE) for electroabsorption modulation [11]. In these applications, it is essential to control the layer thicknesses and material quality with a high precision. MHAH technique provides high materials quality as well as thickness precision. MQWs are one-dimensional periodic structures which can be utilized in various optoelectronic devices like near-infrared photodetectors, electroabsorption modulators based on the QCSE (which yields larger absorption difference than Franz-Keldysh effect for bulk), Ge-on-Si lasers. The on-chip ...

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