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AlGaAs/GaAs microdisk lasers with InAs/InGaAs quantum dots have been transferred to the surface of a silicon wafer using an indium solder. The microlasers have a common electric contact deposited on top of the residual n+-GaAs substrate and individual addressing is ensured by placing the microdisks with the p contact down onto separate contact pads formed on silicon. No effect of a non-native substrate on the electrical, threshold, thermal, and spectral characteristics has been established. The microdisks can operate in continuous-wave regime without forced cooling at a threshold current density of ~0.7 kA/cm2. The lasing wavelength is stable (

The operation speed of microdisk lasers with quantum dots working at room temperature without thermal stabilization has been experimentally examined, and the widest modulation bandwidth of microdisks with various diameters has been calculated. It was shown that taking into account the effect of self-heating of a microlaser at high bias currents, which is manifested in a decrease of the ultimate operation speed and in an increase in the current at which the widest modulation bandwidth is reached, enables a good description of the experimental data. The self-heating most strongly affects microlasers with a small diameter (less than 20 μm).

InGaAs/InGaAlAs laser diodes operating in the 1.55-μm spectral range are studied. It is demonstrated that a certain level of carbon doping (1012 cm–2 per a single quantum well) allows one to reduce the temperature coefficient of variation of the lasing wavelength in such structures and raise the characteristic temperature of threshold current and differential efficiency at temperatures from 16 to ~50°C. These changes are accompanied by an increase in threshold current density and a reduction in differential efficiency.

Injection microlasers with an active region based on arrays of InGaAs/GaAs quantum well-dots, formed by deep etching, have been studied. The manner in which the current–voltage characteristic changes when the diameter microlaser is reduced shows that a nonelectrically conducting layer with thickness of about 1.5 μm is formed near the side surface, which leads to a decrease in the effective current flow area.

We have studied characteristics of a 23-μm-diameter microdisk laser operating in a regime of direct high-frequency modulation at a stabilized heat-sink temperature of 18°C. It is found that the minimum energy consumption in this regime amounts to ~1.6 pJ/bit and is achieved at a modulation frequency of 4.2 GHz. The maximum modulation frequency is 6.7 GHz, at which the minimum energy consumption is 3.3 pJ/bit.

I–V and radiative characteristics of multilayer quantum-cascade GaAs/AlGaAs heterostructures with a double metal waveguide are investigated. The I–V characteristics typical of the quantum-cascade lasers are seen. The observed threshold-intensity growth and narrow radiation spectrum are characteristic of laser generation. The measured radiation frequency was found to be about 3 THz, which coincides with the calculated value. Thus, fully domestic terahertz quantum-cascade lasers are demonstrated for the first time.