Among all binary III-V semiconductors, InSb has the highest intrinsic electron mobility, the narrowest band gap, and the smallest electron effective mass (m* = 0.0139m0). These characteristics make InSb quantum wells (QWs) with remotely doped AlxIn1-xSb barriers promising for several novel devices. The promise of InSb QWs for spin transistors has been shown recently by experiments that demonstrate ballistic transport and a large zero- field spin splitting. Mesoscopic magnetoresistors that take advantage of the high electron mobility in InSb QWs at room temperature are being explored for read head applications. For some applications, the carriers are required to travel ballistically through the channel. Four-terminal structures and quantum point contacts are investigated to explore the unique effects of narrow-gap properties on ballistic transport. For all the applications, there is also a need to increase the room and low temperature mobilities with negligible parallel conduction paths in these quantum well structures.