In this work, we present progress towards device fabrication using purified, semiconducting-enriched SWNT as the base material. Nanotubes were deposited in different densities (low, moderate, and high density) with different gate length of transistors and effect of each parameter has been studied using DC measurements. It is been shown that the nanotube network density plays a significant role in controlling the performance of such devices. By controlling the density of nanotubes in the network, we laid down a road map to predict and enhance the device performance based on their mobility and on/off ratio. From this work the DC analysis of devices characterization shows a mobility more than 90 cm2/V-s and also on/off ratios as high as, 105 have been achieved. We have demonstrated the first density-control technique over the nanotube network as a key point to modify the transistor’s mobility and on/off ratio . When dense network mats of nanotubes were deposited, devices outperformed with higher mobility more than 90 cm2/V-s, enabling a faster switching speed. While relatively low-density mats yielded devices with on/off ratio of more than 105, which makes this technique feasible for low power nanoelectronics. Besides, the effect of various gate lengths have been studied which reveals an interesting trend between the channel length and the mobility.