Influence of growth temperature and structure parameters on optical characteristics InGaAs/GaAs quantum wells

In the last few years the InGaAs/GaAs heterostructure system has received increasing interest for electronic devices and microwave industries. The strained quantum well (QW) laser has more beneficial effect than other QW lasers. For example, lower threshold current density, wider modulation bandwidth and the emission wavelength of strained QW laser can be adjusted by appropriately changing the strain. With regard to InGaAs/GaAs material system, indium distribution influence on the performances of device directly. Surface segregation of In ions during the growth process is the major factor for the indium distribution in InGaAs/GaAs heterostructure. The heteroepitaxy of InGaAs layer on GaAs substrates is characterized by a strong segregation of In atoms that accumulate at the growth front and substantially modifies the In-composition profile, resulting in different electronic and optical properties of the devices based on that material. Segregation determines the composition profiles of QW in the growth direction in many semiconductor systems, and consequently, the quantized levels are strongly influenced. The samples of InGaAs/GaAs strained QW are grown in Riber32 compact 21 solid source molecular beam epitaxy (MBE) system equipped with a valved cracker cell for arsenic and reflection high energy electron diffraction (RHEED) for in situ monitoring of the growth process. Growth temperature is calibrated by infrared pyrometer. The photoluminescence (PL) was studied on InGaAs/GaAs strained QW with various different growth temperature and structure parameters. In ions segregation processes was illustrated based on the Muraki model and the differential calculation were compared with experiment results in detail. The results show that some important information was obtained about the effect of indium segregation, desorption and In-Ga intermixing on optical quality of strained quantum well. The effect is serious, and the peak position of PL is blue shifted with increasing the growth temperature. It is demonstrated that indium segregation and In-Ga intermixing have no effect on the optical properties of InGaAs/GaAs strained quantum well with In content below x = 0.2 and the growth temperature below 560 °C by PL analysis.