Much effort has been spent developing theoretical models and understanding peculiar nitrogen-induced effects on optical properties of dilute nitrides [1, 4–6]. Although the strong composition dependence of the bandgap energy compared to the
conventional III-V alloys is attractive, it has been soon realized that the presence of nitrogen severely degrades the optical quality. Therefore, thermal annealing is commonly used a standard procedure to improve the optical quality of dilute nitrides, but at the expense of the blueshift of the bandgap [1, 7]. From the electronic properties’ point of view, it has been demonstrated that incorporation of nitrogen gives rise to drastic decrease in electron mobility due to the N-induced www.selleckchem.com/products/MLN-2238.html scattering centers and selleckchem enhanced electron effective mass [8–13]. On the contrary, in the presence of the nitrogen, it has been theoretically demonstrated that hole effective mass and hole mobility remain unaffected [14–16]. So far, much effort has been focused on nitrogen dependence of electron effective mass and electron mobility, ignoring the composition dependence of hole effective mass and hole mobility. Moreover, even it has been accepted as a standard procedure to improve optical quality,
the effects of thermal annealing on electronic properties has not been considered. The aim of the study presented here is to investigate the effect of nitrogen composition and thermal annealing on electronic transport properties eltoprazine of n- and p-type modulation-doped Ga0.68In0.32N y As1 – y /GaAs (y = 0, 0.009, and 0.012) strained
quantum well (QW) structures. Methods The samples were grown on semi-insulating GaAs (100) substrates using solid source molecular beam epitaxy, equipped with a radio frequency plasma source for nitrogen incorporation. XRD measurements were used to determine nitrogen and indium compositions. The sample structures are comprised of 7.5-nm-thick QW with indium concentration of 32% and various nitrogen concentration (N% = 0, 0.9, and 1.2) and 20 nm doped (Be for p-type and Si for n-type) GaAs barriers. A 5-nm GaAs was used between GaInNAs and GaAs layer to separate charge and doping regions. The growth temperatures of GaInNAs, GaInAs, and GaAs were 420°C, 540°C, and 580°C, respectively. Post growth rapid thermal annealing was applied at 700°C for 60 and 600 s. The doping density was the same for both n- and p-type samples as 1 × 1018 cm-3. The samples were fabricated in Hall bar shapes, and ohmic contacts were formed by alloying Au/Ge/Ni and Au/Zn for n- and p-type samples, respectively. Magnetotransport measurements were carried out using a 4He cryostat equipped with a 7 T superconducting magnet. In-plane effective mass, 2D carrier density, and Fermi energy were determined by analyzing the Shubnikov de Haas (SdH) oscillations as a function of temperature between 6.1 and 20 K.