Removal of Methylene Blue by Activated Glass Foams with TiO 2 in Dark and Simulated Solar Light

• Published in: Annals of the West University of Timisoara, Physics Series Vol. 61; no. 1; pp. 33 - 43
• Main Authors: Rus, Florina Stefania, Novaconi, Stefan Danica, Vlazan, Paulina, Ivanovici, Madalina
• Format: Journal Article
• Language: English
• Published: 01-12-2019
• ISSN: 1224-9718; 1224-9718
• DOI: 10.2478/awutp-2019-0003

The effect of germanium trapezoidal profile shape on the direct current (DC) current gain (βF), cut-off frequency (fT) and maximum oscillation frequency (fMAX) of silicon-germanium (SiGe) hetero-junction bipolar transistors (HBTs) has been investigated. The energy balance (EB), hydrodynamic (HD) and drift-diffusion (DD) physical transport models in SILVACO technology computer aided design (T-CAD) simulator were used. It was found that the current gain values using energy balance model are higher than hydrodynamic and much higher than those corresponding to drift-diffusion. Moreover, decreasing the germanium gradient slope towards the collector side of the base enhances the maximum oscillation frequencies using HD and EB models whilst, they remain stable for DD model.