I am often too tired to get up and write down dreams in my dream journal. Sometimes I’m too tired to even write down notes 
What should I do?
Maybe using a voice recorder would do the thing?
hmm… maybe.
Maybe autosuggestion would also work. But that’s just a theory.
Sometimes when you wake up in your sleep cycle dictates how sleepy you can be. Also, are you getting enough sleep? That can always be an issue. 
I’ve found that my dream journal has to be something I can do in bed in the dark while half-asleep, otherwise it doesn’t get done. I use a journal app on an iPod touch, which I keep on my nightstand. I can grab it and barely move from my position, and type on it without sitting up or getting out of bed, or turning on the light. Maybe keeping a journal on some small device like that would work better for you?
Here’s a neat idea: most modern phones have a voice recording feature. Keep the phone right by your bed (or even use it as an alarm) and upon waking up, start the recording and say the first things that come to your mind. Later, when you’re a bit more alert, you can replay the recording and flesh out the idea more fully as a journal entry.
I would say just force yourself to wake up and do it. I myself feel so tired in the morning, I just want to roll over and go back to sleep.
Then I always forget the cool dream I had, and slap myself for it later. Don’t let your mind be lazy, write down your dreams! 