Say, you want to make a digital logic circuit made of fast n type and p type

devices. You have materials A,B,C,D to choose from. The ratio of electron

effective masses for materials A,B,C and D is 1:2:4:3. The ratio of hole

effective masses for materials A,B,C and D are 4:1:3:2. Which materials from

A,B,C and D you would like to choose for making those fast n type and p type

devices?