I want to reduce the number of broadcast domains inside my network, Which device I should install in my network ?

Adding L3 switch device and different VLAN ranges to segregate data traffic.

If you want to reduce the number of broadcasts domains it is better to use a layer2 switches with a suitable IP scheme and if you need to reduce the size of your broadcast domain then u need at least one layer 3 device and layer 2 devices where you create the VLANs with a suitable IP scheme.

A router is added,L3 breaks broadcast domains.

By applying different vlan it will increase the broadcast domain number but it will decrease the size of broadcast

If u want to decrease the no of broadcast domain decrease the vlan 

If u don't need the vlan network just use layer 2 or 3 switch there will be one broadcast domain.

Make Vlans in L2 Switch or Use Routers

Any layer 3 device would work, layer 3 switch or a router. VLANs configuration is a must.

layer 3 network device router or you can use layer 3switch

If we have switch network we can create VLAN's to divide network in logical groups therefore separating broadcasts in a network. Now as switch technology has evolved and routing function can also be performed those are known as layer 3 switches. So, we can implement L2 or L3 switch to implement VLAN's to decrease broadcast in a network.  

Use a L3 Switch and create vlan to reduce the broadcast.

to reduce the number of Broadcast Domain you can divide your network by applying V-lan for each department in your company to sub divide the network , you can u Switch to apply V-lan 

divide network into separated VLAN and we can use L3 switch iw we need to route between these vlans