Nominally undopedn‐type single crystals of ZnGeP2have been fabricated for the first time by high‐pressure vapor transport. These crystals have higher phosphorus concentration than melt‐grown bulk single crystals and exhibit lower sub‐band‐gap absorption in the transparency range between 0.64 and 12 &mgr;m. A heretofore unreported absorption peak at 13 &mgr;m and a transparency window extending from l5 &mgr;m to at least 23 &mgr;m have been identified in the infrared for these crystals, as well as in crystals grown from melt.