1. Where are carbon atoms forced to go in GaAs with less Ga(CH3)3 and more AsH3?

2. Can you guess why there is a singularity in the figure where the net carrier concentration goes to zero? You can assume that the total carbon concentration in GaAs is constant.

Carrier Concentration (cm) (e) The following figure shows how the ratio of AsH3 to Ga(CH3)3 partial pressures in MOCVD affects the conduction type (n or p) and net carrier concentration of the GaAs film (S. Ito, T. Shinohara, and Y. Seki, Journal of the Electrochemical Society, vol. 120, p. 1419 (1973)). With more Ga(CH3)3 and less AsH3, the GaAs film becomes p-type. With less Ga(CH3)3 and more AsH3, the GaAs film becomes n-type. You can find help for the following questions in my paper: M. Tao, Journal of Applied Physics, vol. 87, p. 3554 (2000). 108 106 10 p-type Model Model n-type GaAs(001) 10 AsH /Ga(CH) Ratio 10