In this paper, we present the length reduction of optoelectronic sensors using conductometric InGaAs/GaAs helical nanobelts. The helical nanobelt contributes to improve the unit length responsivity of photodetector while maintaining high external quantum efficiency (EQE) per unit length. A nanorobotic assembly and characterization of 3-D helical nanobelts to create in-/out-of-plane optoelectronic sensors has been shown. High optoelectronic sensitivity was revealed from experimental investigation under an optical microscope and from light emitting diodes (LEDs) inside a scanning electron microscope (SEM). A probe type photodetector was assembled using nanorobotic manipulation and in-situ gold nanoparticle ink soldering.