Experimental and theoretical study of quantum dot resonant tunneling diodes for single photon detection

Single photon detection has a broad application in the medical, telecommunication, as well as in infrared imaging fields. In this thesis I present my work in studying quantum dot (QD) resonant tunneling diodes (RTD) for single photon detection. The device was processed in the form of a free-standing small-area air bridge. A detailed series of experimental and theoretical characterizations have been performed to understand the electrical properties of the RTDs (without embedding any QDs) and QD-embedded RTDs (QDRTDs). It has been shown that external series and parallel resistances shift the resonant current peak to higher voltage, create the bistability effect observed in I-V characteristics, and reduce the peak-to-valley ratio. For the QDRTD device, three-dimensional wave packet carrier transport simulations show strong influence of the long-range Coulomb potential induced by the hole captured by the embedded InAs QDs, thus demonstrating the fundamental principle of single photon detection. Two works are planned for the continuation of the graduate study after Lic examination. The optical response of the QDRTD will be experimentally and theoretically characterized in order to optimize the quantum efficiency for single photon detection. I will then concentrate on processing a one-dimensional photodetector array aiming at practical biotechnology applications.QC 2010111