Is there a supplication (dua) before sleep that helps one wake up easily for Fajr prayer?

There is no specific supplication from the Prophet, peace and blessings be upon him, for waking up for Fajr prayer. However, there are matters that can help with this: sleeping early, taking a nap (qailulah), contemplating the immense reward for performing Fajr prayer in congregation, and reflecting on the seriousness of missing it due to sleep.