Strain, pressure and temperature effects on linear and nonlinear optical properties of InP/InAs_1−xP_x/InP quantum well heterostructures

Optimizing the parameters that control the InAsP/InP quantum well (QW) system is of utmost importance for this system to give the best yield. Beginning from QW energy levels and momentum matrix element calculation, this work studies linear, nonlinear absorption and refractive index change, second harmonic generation (SHG), and third-harmonic generation (THG) in InAsP/InP QWs. Parameters controlling the structure, like hydrostatic pressure, temperature, well width, and phosphor mole fraction, are studied. The results show that the difference between energy levels increases with increasing temperature or reducing pressure. These differences are essential in obtaining SHG and THG. Pressure is more effective than the temperature in changing energy differences while increasing phosphor reduces the energy difference. So, one can choose the adjusted parameter (pressure or composition) according to the change in energy required. The pressure reduces absorption while temperature increases it. Increasing phosphor mole fraction reduces absorption; at high mole fraction, the absorption is approximately constant. The total refractive index change (RIC) is reduced with pressure or increasing molarity, but the higher molarity increases RIC. Increasing phosphor mole fraction reduced SHG and vice versa to THG. Increasing temperature increases SHG, and blue shifts its peak. For the pressure, it reduces SHG and redshifts its peak. Pressure increases THG and redshifts its peak while the temperature blue shifts THG peak. The effect of the temperature on the peak of the THG depends on the pressure: the temperature reduces the peak at low pressure, while the temperature increases it at high pressure. The results show the importance of such a study because the optical properties do not have a single-parameter effect; it has an interference effect of many parameters to produce the result.