Investigations On The Epitaxial Growth And Devices' Fabrication Of Bimodal-sized InGaAs/GaAs Quantum Dot

Since the concept of low dimensional semiconductor material has been put forward,it raised a research burst about the physics mechanism and experimental fabrication.Until now,the research about the physics mechanism and experimental fabrication of semiconductor quantum well(QW)devices has become perfect,commercial QW devices have widely involved people's daily life.Quantum dots(QD)devices which have lower dimensions,due to the ? state electron wave function,have superior performance than QW in terms of theory and become research focus in recent years.However,it has been demonstrated by experimental results that the QD devices performance is not ideal compare to theoretical prediction,even less well than QW devices,especially in the field of semiconductor lasers.Although the research of QD appeared the trend of stalemate,in some specific applications such as ?-? light emitting devices on Si,Single photon source device and so on,QD have the natural advantages which the QW and bulk materials cannot replace and become new research hotspot.In this paper,we demonstrated a deliberately grown quantum dot with bimodal-sized and the superluminesent diode(SLD)and dual-wavelength laser using this material as active layer.The main contents of the paper are as follows:1.Investigate the growth parameter of QD under self-organization mode in MOCVD system,such as growth temperature,growth rate,?/? ratio,growth interruption,coverage and so on,and ensure the growth window.Under growth temperature of 530°C,growth rate of 1.64 ML/s,?/? ratio of 45,growth interruption of 10 s and coverage of 5.26 ML,we got the QDs with obviously bimodal-sized feature.The large dots are 4.8nm in height and the small dots are 3.5nm in height.2.a high-power and broadband superluminescent diode is achieved utilizing bimodal-sized quantum dots(QDs)as active materials.The device exhibits a 3 d B bandwidth of 178.8 nm with output power of 1.3 mW under continuous-wave(CW)conditions.Preliminary discussion attributes the spectra behavior of the device to carrier transfer between small dot ensemble and large dot ensemble.Our result provides a new possibility to further broadening the spectral bandwidth and improving the CW output power of QD-SLDs.3.We demonstrate high power,dual-wavelength(dual-?)lasing stemming from bimodal-sized InGaAs/GaAs quantum dots(QDs).The device exhibits simultaneous dual-? lasing at 1015.2 nm and 1023.0 nm with total power of 165.6 mW at 700 mA under room temperature continuous wave(CW)mode.Gaussian fitting analyses of the electroluminescence(EL)spectrum attribute the excellent performance to independent carrier transitions from the first excited states of large dot ensemble(LD ES1)and small dot ensemble(SD ES1),respectively.This formation provides a new possibility to achieve high power dual-? operation only using Fabry-Pérot(FP)cavity,which is significant for compact size and low fabrication cost.