Quantum Dot Infrared Photodetectors by Metal-Organic Chemical Vapour Deposition

This chapter examines that the InAs QDIPs based on the GaInAs/AlInAs/InP system are demonstrated by MOCVD. The dependence of the dot formation on the MOCVD growth conditions are systematically studied and characterized. High-density, uniform InAs quantum dots (QD) are obtained at the optimum conditions. On the basis of such QDs, several QDIP device structure are fabricated and characterized. The wavelength tunability of the QDIPs is realized within a certain range. With the improvement of structure design and material quality, some of the devices have outperformed the corresponding QWIP. A 320 256 MWIR FPA based on our high-performance QDIP is demonstrated. Imaging at temperatures up to 200 K is demonstrated. The chapter illustrates that QDs are the key element of the device. The dot size directly affects the detection wavelength. The shape of the dot may affect the oscillator strength and thus quantum efficiency. The density and uniformity affect device performance such as responsivity and detectivity. Thus, it is crucial to have high-density and uniformity QDs and still maintain the right size.