We determined the lateral mobility of photocarriers and activation energy of the photocurrent (PC) in stacked InAs quantum dot (QD) layers with ultrafast carrier relaxation times and 1.5-μm band absorption. Lateral mobility is one of the important parameters in the application of QD layers to photoconductive antennas operating with 1.5-μm gating light for terahertz (THz) wave detection. The activation energy obtained from temperature dependence of PC spectroscopy is important for elucidating the mechanism, and it is an indicator of the temperature range for antenna operation. The dependence of the mobility on the photocarrier density was evaluated from the dependence on the pump power. The mobility sharply increased from 42 cm²/V･s in the dark to 416 cm²/V･s upon laser illumination and then decreased with the increase in the number of generated photocarriers. The broad PC peak from InAs QD layers at around 1400 nm was continuously monitored in the temperature range of 4–292 K. The activation energy of the PC from the InAs QD layers was evaluated in the temperature range of 159–240 K where the PC significantly increased. In the broad PC peak in the wavelength range of 1200–1600 nm, the activation energy increased from 48 to 62 meV with the wavelength. The PC observed at lower temperatures was not derived considering the thermal escape of electrons, but it was determined through the Auger process. The InAs QD layer with ultrafast carrier relaxation has considerable potential in photoconductive antenna applications for THz wave detection.

我们确定了具有超快载流子弛豫时间和1.5μm吸收带的堆叠InAs量子点（QD）层中光载流子的横向迁移率和光电流（PC）的活化能。横向迁移率是将QD层应用到以1.5μm选通光工作的太赫兹（THz）波检测的光电导天线中的重要参数之一。从PC光谱的温度依赖性获得的活化能对于阐明机理很重要，它是天线工作温度范围的指标。从对泵浦功率的依赖性来评估迁移率对光载流子密度的依赖性。迁移率从黑暗中的42 cm ² / V ･ s急剧增加到416 cm ²/ V ･ s在激光照射下，然后随着所产生的光载流子数量的增加而降低。在4–292 K的温度范围内连续监测InAs QD层在1400 nm处的宽PC峰。在159–240 K的温度范围内评估InAs QD层的PC的活化能显着提高。在1200-1600 nm波长范围内的宽PC峰中，活化能随波长从48 meV增加到62 meV。考虑到电子的热逸散，并不能得出在较低温度下观察到的PC，而是通过俄歇过程确定的。具有超快载流子松弛能力的InAs QD层在用于THz波检测的光电导天线应用中具有巨大潜力。