diff --git a/src/main.py b/src/main.py
index 1992481..ece1ef5 100644
--- a/src/main.py
+++ b/src/main.py
@@ -133,7 +133,6 @@ def deduplicate_instruments_from_layers(layers):
     #     "deposition_chamber": chambers,
     #     "rheed_system": rheeds,
     # }
-    return instruments_used_dict
 
 def make_nexus_schema_dictionary(substrate_object, layers):
     '''
@@ -391,6 +390,17 @@ def build_nexus_file(pld_fabrication, output_path):
                 nx_post_annealing["duration"].attrs["units"] = post_ann_dict["duration"]["units"]
             except TypeError as te:
                 raise TypeError(te)
+        
+        # Instruments used section
+        nx_instruments = nx_pld_entry.create_group("instruments_used")
+        nx_instruments.attrs["NX_class"] = "NXinstrument"
+        instruments_dict = pld_fabrication["instruments_used"]
+        try:
+            nx_instruments.create_dataset("laser_system", data = instruments_dict["laser_system"])
+            nx_instruments.create_dataset("deposition_chamber", data = instruments_dict["deposition_chamber"])
+            nx_instruments.create_dataset("rheed_system", data = instruments_dict["rheed_system"])
+        except TypeError as te:
+            raise TypeError(te)
     return
 
 if __name__=="__main__":