E.K.
We had the same issue with my son when he first turned two. Here's what we did:
First, he needs a bedtime that is the same every night. Even 20-30 minutes different is too much. Our son goes to bed at 8:00am and wakes up at 6:45. It's the same every night/morning. Then, we got him a lamp that has a really low setting - it acts as a nightlight. Then we got him a flashlight - Target has a really great one. It has three settings and one of the settings makes the body of the flashlight "glow". Kinda like a glow stick. He keeps this in bed with him on the "glow" setting. Then, the last thing we did (and yes some will disagree with it) - we told him that if he cried, then we'd close his door at night. If he stayed quiet and stayed in bed we could leave the door cracked open. He resisted a few nights and we gave one warning before we closed the door. He would go to the door and cry then. So, we put up a baby gate so that he couldn't leave the room. That made him mad! So, we let him cry for a while, then came in and explained that the door could remain cracked open and the gate would come off if he quieted down and stayed in bed. And we told him that if he continued to cry, we'd take his flashlight away.
You may think that your child is unable to get this concept so young, but trust me, he's not. We had about a week of struggling with this, but then it got better. He's two and a half now and goes to bed with no issues now. However, he LOVES that flashlight and won't go to bed without the flashlight and his kitty (stuffed animal).