We describe the production of mid-infrared (mid-IR) short carbon dioxide (CO2) laser pulses with variable durations from 3 to 15 ns at a maximum pulse energy of 150 mJ/pulse using a germanium (Ge) substrate semiconductor switch and a multipass amplifier. The results clearly show the spectral profiles possess all of the desired characteristics as well as the possibility of obtaining an energy conversion efficiency close to the theoretical upper limit. It is also shown that it is necessary to irradiate with pulse durations less than 10 ns to optimize efficient EUV emission using Sn and Gd targets.