If you want width, you must row. This workout is great on its own, but is also an ideal approach if you like to do two back days a week, one focused more on horizontal pulls, the other on vertical pulls. That's the approach taken in the popular program 30-Day Back with Abel Albonetti.
Row-to-Grow Back Day
4 sets, 6-8 reps (rest 2 min. )
3 sets, 10-12 reps (rest 1 min. )