Bismuth surfactant effects for GaAsN and beryllium doping of GaAsN and GaInAsN grown by molecular beam epitaxy

Kinetically limited growth of GaAsBi by molecular-beam epitaxy

“…This indicates that either As atoms outcompete Bi atoms for incorporation sites or that Bi simply prefers, for energetic reasons, to be on the surface rather than in the bulk. Segregated Bi is a very effective surfactant, leading to much smoother surfaces at these unusually low growth temperatures and As fluxes than comparably grown GaAs without a Bi surfactant [6][7][8][9]. However, substantial unincorporated Bi on the surface leads to the formation of Bi droplets and an apparent limit to the maximum concentration of Bi that can be incorporated for a given set of growth conditions [9,10].…”

Improved performance of GaInNAs solar cells grown by molecular-beam epitaxy using increased growth rate instead of surfactants

“…It is possible to suppress this roughness in a number of ways. Surfactants such as Sb and Bi are very efficient at reducing roughness [6,7,12,13], but each one increases the defect density (leading to lower device performance) and changes the carrier concentration (leading to low depletion widths and low photocurrents) [6,7,11]. It is also possible to get smooth morphologies by lowering the In content, but for 1.0 eV GaInNAs solar cells, this obviously produces strained material that has a good chance of forming extended defects during the growth of the 3-mm-thick base layer.…”

“…Surfactants such as Sb and Bi have had great success in eliminating the In segregation and providing smooth surfaces even at high temperatures and In contents [6,7,12,13]. Unfortunately, both Sb and Bi have other problems, including an increase in the net acceptor concentration (Sb) [6,7] or net donor concentration (Bi) [11].…”

Effects of Mg doping on the electrical and luminescence characterizations of p-type GaAsN alloys grown by MBE

“…From a physical standpoint, impurity doping generally affects the electrical and luminescence characterizations of semiconductors. There are several repots on intentionally acceptor-doped p-type (In)GaAsN alloys grown by MBE [5,15,[18][19][20][21][22][23], where beryllium (Be) is used as an acceptor element and the maximum hole concentration is $ 1 Â10 19 cm À 3 for Be-doped (In)GaAsN alloys.…”

“…As mentioned above, several authors have used Be as an acceptor element for p-type (In)GaAsN alloys [5,15,[18][19][20][21][22][23]. However, Be doping into (In)GaAsN alloys leads to N composition fluctuation [19]; the N composition increases with increasing the Be concentration.…”