Studies on Material based Performance Analysis of Advanced Photonic Devices

Abstract

Transistor lasers and solar cells are an important device of a nanophotonics or optoelectronic system. Photovoltaic devices and heterojunction bipolar transistor laser (HBTLs) have received a significant attention due to their vast applications in various area of science and engineering respectively. The present thesis put emphasis on theoretical studies on HBTL and solar cell. The application of HBTL is focussed in optical telecommunication and mid infrared spectral regions with focus on the utilization of group III-V, group IV and III-V nitrides. The analysis is performed starting from multiple quantum well (MQW) transistor laser (TL) with tunnel injection (TI) phenomenon for InGaAs-GaAs material at a wavelength of 1550 nm. The MQW TL-TI performance is discussed in terms of threshold current density and small signal modulation response. The threshold current density and modulation bandwidth of a TL having a tunnel injection structure at the emitter end and MQW in the base are studied. The terminal currents are obtained from the continuity equation solution. Transfer of carriers from bulk to the sub-bands in the QW is assumed to occur via virtual states. The Statz-De Mars laser rate equations are solved to obtain the small signal modulation response. The optimum value of threshold base current, light power output, confinement of carrier etc. are estimated for three InGaAs QWs embedded into the base. With the incorporation of tunneling mechanism, base threshold current reduces and modulation response increases as compared to conventional TL with MQW in the base. newline