In this work, the In desorption behavior in the molecular-beam-epitaxy (MBE) growth of InGaAs/GW4869 clinical trial AlGaAs MWIR QWIP was studied. With low-temperature capping technology of a thin AlGaAs,

the In composition can be well controlled. Methods The samples in this work were grown on a Si-GaAs substrate by a VG-80H MBE system and divided into two groups assigned as groups I and II. The growth rates were firstly determined by reflection high-energy electron diffraction and finely calibrated by X-ray diffraction (XRD) and photoluminescence AMN-107 datasheet (PL) measurement. Group I including samples A, B, and C were used for observing the In composition-losing behavior in InGaAs. Figure 1a,b shows the growth procedure illustrations of samples A and B, respectively. Sample C was a complete replica of sample A. Figure 1 Procedure schematics Gemcitabine in vitro of (a) sample A, (b) sample B, (c) sample D, and (d) sample E. In order to demonstrate the effect of a low-temperature thin AlGaAs capping layer on suppressing the In desorption, group II including samples D, E, and F were grown. All the three samples were designed to have the same structure with a peak

absorption wavelength from the inter-subband transition in InGaAs/AlGaAs quantum wells around 4.3 μm. The layer sequence of the sample structure is 1 μm Si-GaAs bottom contact layer, 20 periods of quantum wells consisting of 50 nm Al0.4Ga0.6As barrier, 0.5 nm GaAs, 2.7 nm In0.3Ga0.7As, and 0.5 nm GaAs. Then, 500 nm Si-GaAs top contact layer was grown to finish the structure. The growing details of samples D and E were displayed in Figure 1c,d, respectively. Finally, we prepared

another sample F using the same growth procedure of sample E. Results and discussions Considering the obvious growth temperature difference between InGaAs and AlGaAs, it is wise to grow InGaAs quantum well under low temperature, then increase the growth temperature to grow the AlGaAs barrier in order to achieve best crystal quality. It is without a doubt that such growth procedure will decrease the In composition in the InGaAs quantum well. However, if the In BCKDHB atom desorption behavior is predictable and repeatable, it is still possible to grow a determined In composition quantum well through the growth of an InGaAs layer with higher In composition to compensate the In loss during the increase of substrate temperature. So, we firstly design an experiment to study such phenomenon. Because both the quantum well composition and thickness contribute to the inter-band transition energy, it is impossible to determine the structural characteristics of the quantum well by PL directly. Besides, the InGaAs quantum well is as thin as around 2.7 nm in the 4.3 μm QWIP, it is also very hard to measure the precise composition by XRD technology. In order to quantitatively explore the In composition-losing behavior in the quantum well, samples A and B were grown.