[17a-Z18-1~10] 9.2 Nanoparticles, Nanowires and Nanosheets

▲ [17a-Z18-8] On Controlling Charge Carrier Transport in Colloidal Quantum Dot Assemblies

〇Satria Zulkarnaen Bisri^1,2, Ricky Dwi Septianto^1,2, Retno Miranti¹, Nobuhiro Matsushita², Yoshihiro Iwasa^1,3 (1.RIKEN-CEMS, 2.Tokyo Inst. Tech., 3.Univ. Tokyo)

Keywords:colloidal quantum dots, charge carrier transport, field-effect transistors

Here we establish a framework to understand the charge carrier transport of various QD assemblies acquired from FET measurements. The merit of FET is its capability to allow us to modify the charge carrier density in the assembly by field-induced doping. It strongly depends on how the coupling of the gate system to the probed materials that act as the FET channels. The QD assemblies' surface quality varies by different assembly methods, existing facet conditions, assembly orders, etc. Therefore, they become factors in comparing the use of solid gate and conformational gate, which are electrolyte gate (including ionic liquid gate) or top-deposited polymer gate. Besides the formed electric field by the gating, the dielectric coefficient of the QD, which is influenced by the quantum confinement effect, may also play a role in deciding how thick the charge accumulation layer is. The influence of the doping-like effect in the FET measurement outcomes, both in transfer characteristics and carrier injection characteristics, will be discoursed. Furthermore, the observations of band-filling effect at high carrier density accumulation in several Pb-chalcogenide systems will be reviewed and rethinking the occurrence of band half-filling as the gauge to determine many other parameters related to carrier concentration, mobility, and traps.