Teen and technology addiction?

Dear Nicholeen, I need help with my 17 year old son, who is soon turning 18. He is constantly on his phone and computer to the point that it hard to have a conversation with him and connect. As soon as he arrives home he normally goes to his room and starts working on his school work. He is taking several AP classes in his senior year and has been able to keep good grades. My concern is the long hours in front of the screens. After school, he would normally spend 6-8 hours on his computer doing homework, talking to friends, and gaming. He stays up until 1-2 am and struggles with waking up and at school he is falling asleep in class. I have also noticed that he is not interested in applying for college. He is a bright kid and I am worried his technology utilization is now an addiction that is not allowing him to find plan for his future. To correct his behavior we have asked him to learn to manage his time and shut all electronics by latest 11 pm. He would follow this for a few days and he goes back to the old routine. We are thinking of removing all electronics, but wonder if there are other approaches given his age. Please advice. Thank you, CA