We demonstrate the control of the quantum-confined Stark effect in InGaNGaN quantum wells (QWs), grown along the [0001] direction as part of the active region of visible light emitting diodes (LEDs). The effect can be altered by modifying the strain applied to the active region by the hole injection and contact layers. The optical characteristics and electrostatic potentials of the active region of the visible LEDs with different p -type layers are compared. LEDs with p-InGaN on top of the active region show a reduced blueshift in the peak wavelength with increasing injection current and a lower potential difference across the QW than those with p-GaN layers. The electrostatic potentials across the QW have estimated average values of ∼0.8 and ∼1.3 MVcm for the active region of LEDs of current study with p-InGaN and p-GaN layers, respectively. © 2008 American Institute of Physics.